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Moving cursor when maxlength in jQuery [duplicate]

How can I focus the next input once the previous input has reached its maxlength value?
a: <input type="text" maxlength="5" />
b: <input type="text" maxlength="5" />
c: <input type="text" maxlength="5" />
If a user pastes text that is greater than the maxlength, ideally it should spill into the next input.
jsFiddle: http://jsfiddle.net/4m5fg/1/
I must stress that I do not want to use a plugin, as I'd much rather learn the logic behind this, than use something that already exists. Thanks for understanding.

No jQuery used and is a very clean implementation:
Reads from the maxlength attribute.
Scales to any number of inputs inside of your container.
Automatically finds the next input to focus.
No jQuery.
http://jsfiddle.net/4m5fg/5/
<div class="container">
a: <input type="text" maxlength="5" />
b: <input type="text" maxlength="5" />
c: <input type="text" maxlength="5" />
</div>
..
var container = document.getElementsByClassName("container")[0];
container.onkeyup = function(e) {
var target = e.srcElement || e.target;
var maxLength = parseInt(target.attributes["maxlength"].value, 10);
var myLength = target.value.length;
if (myLength >= maxLength) {
var next = target;
while (next = next.nextElementSibling) {
if (next == null)
break;
if (next.tagName.toLowerCase() === "input") {
next.focus();
break;
}
}
}
// Move to previous field if empty (user pressed backspace)
else if (myLength === 0) {
var previous = target;
while (previous = previous.previousElementSibling) {
if (previous == null)
break;
if (previous.tagName.toLowerCase() === "input") {
previous.focus();
break;
}
}
}
}

You can watch for input in the fields and test its value:
$("input").bind("input", function() {
var $this = $(this);
setTimeout(function() {
if ( $this.val().length >= parseInt($this.attr("maxlength"),10) )
$this.next("input").focus();
},0);
});
Working demo.
The setTimeout is there to ensure the code will only run after the input is completed and the value updated. Binding input ensures most types of input will trigger the event, including key presses, copy/paste (even from mouse) and drag & drop (though in this case, the latter won't work, since the focus was on the draggable, not the droppable).
Note: on some older browsers, you might also need to bind propertychange.
If a user pastes text that is greater than the maxlength, ideally it should spill into the next input.
To do that, you might need to remove the maxlength attribute using JavaScript (to be able to capture the full input), and implement that functionality yourself. I made a small example, relevant parts below:
$("input").each(function() {
var $this = $(this);
$(this).data("maxlength", $this.prop("maxlength"));
$(this).removeAttr("maxlength");
})
This removes the attribute, but saves it in data, so you can access it later.
function spill($this, val) {
var maxlength = $this.data("maxlength");
if ( val.length >= maxlength ) {
$this.val(val.substring(0, maxlength));
var next = $this.next("input").focus();
spill(next, val.substring(maxlength));
}
else
$this.val(val);
}
Here the max length logic is reintroduced in JavaScript, as well as getting the "discarded" part and using it in a recursive call to spill. If there's no next element, the call to data will return undefined and the loop will stop, so the input will be truncated in the last field.

You can use plain JavaScript:
See DEMO.
Check the character length with el.value.length. If it is equal to the maximum value, move to the next field by using focus(). Bind this function to the keyup event with onkeyup so that the function fires every time after the user keys in a character.
var a = document.getElementById("a"),
b = document.getElementById("b"),
c = document.getElementById("c");
a.onkeyup = function() {
if (this.value.length === parseInt(this.attributes["maxlength"].value)) {
b.focus();
}
}
b.onkeyup = function() {
if (this.value.length === parseInt(this.attributes["maxlength"].value)) {
c.focus();
}
}

if you are going to have many fields you can do something like this.
basically on keyup get the length of the input and then compare it to the maxlength, if matches, then focus onto the next input field.
http://jsfiddle.net/btevfik/DVxDA/
$(document).ready(function(){
$('input').keyup(function(){
if(this.value.length==$(this).attr("maxlength")){
$(this).next().focus();
}
});
});

let otp = document.querySelector('#otp-screen');
for(let pin of otp.children) {
pin.onkeyup = function() {
if(pin.nextElementSibling) {
pin.nextElementSibling.focus();
}
}
}
<div class="otp-screen" id="otp-screen">
<input type="text" placeholder="0" maxlength="1"/>
<input type="text" placeholder="0" maxlength="1"/>
<input type="text" placeholder="0" maxlength="1"/>
<input type="text" placeholder="0" maxlength="1"/>
</div>

Updated btevfik code, Onkeyup or onkeydown will create issue as you won't be able to delete the previous input on tab navigation. It will be tough to edit or change the text inside the input box as it will be limited to maxlength. So we can use oninput event to achieve the task.
DEMO
HTML
<ul>
<li>a: <input type="text" maxlength="5" /></li>
<li>b: <input type="text" maxlength="3" /></li>
<li>c: <input type="text" maxlength="5" /></li>
<li>d: <input type="text" maxlength="3" /></li>
<li>e: <input type="text" maxlength="6" /></li>
<li>f: <input type="text" maxlength="10" /></li>
<li>g: <input type="text" maxlength="7" /></li>
</ul>
Javascript
$(document).ready(function(){
$('input').on("input", function(){
if($(this).val().length==$(this).attr("maxlength")){
$(this).next().focus();
}
});
});
CSS
ul {list-style-type:none;}
li {padding:5px 5px;}

Other answers do give some idea how this can be implemented, but I find that they do not consider some minor things among which are:
The fact, that you do not want to auto-focus any elements across whole page, but rather within specific form.
Input elements can be wrapped in some other elements (for example I wrap them in span or div to allow floating labels through CSS, and I've seen forms that use table to for structure).
Validity of the field, when spilling over or moving to next one automatically.
Input events when spilling over.
Cursor position when returning to previous field (it looks like it can be saved by browser, thus backspacing can focus not in the end of the field, but, for example, in the middle).
Below code is trying to account to all of this, at least. Most of it can be tested on codepen: paste-spilling does not work there, looks like because of Clipboard API (other codepens with it do not work for me either).
Let me know if anything is unclear in the code, I'll update my answer and the code. If you find some edge case that is not covered - let me know as well.
For paste-spilling test using form from codepen, you can use something like this: 123456789123456789012345678903454353434534
Video sample of how it works in a more "live" envitonment on youtube
//List of input types, that are "textual" by default, thus can be tracked through keypress and paste events. In essence,
// these are types, that support maxlength attribute
const textInputTypes = ['email', 'password', 'search', 'tel', 'text', 'url', ];
formInit();
//Add listeners
function formInit()
{
document.querySelectorAll('form input').forEach((item)=>{
if (textInputTypes.includes(item.type)) {
//Somehow backspace can be tracked only on keydown, not keypress
item.addEventListener('keydown', inputBackSpace);
if (item.getAttribute('maxlength')) {
item.addEventListener('input', autoNext);
item.addEventListener('change', autoNext);
item.addEventListener('paste', pasteSplit);
}
}
});
}
//Track backspace and focus previous input field, if input is empty, when it's pressed
function inputBackSpace(event)
{
let current = event.target;
if ((event.keyCode || event.charCode || 0) === 8 && !current.value) {
let moveTo = nextInput(current, true);
if (moveTo) {
moveTo.focus();
//Ensure, that cursor ends up at the end of the previous field
moveTo.selectionStart = moveTo.selectionEnd = moveTo.value.length;
}
}
}
//Focus next field, if current is filled to the brim and valid
function autoNext(event)
{
let current = event.target;
//Get length attribute
let maxLength = parseInt(current.getAttribute('maxlength'));
//Check it against value length
if (maxLength && current.value.length === maxLength && current.validity.valid) {
let moveTo = nextInput(current, false);
if (moveTo) {
moveTo.focus();
}
}
}
async function pasteSplit(event)
{
let permission = await navigator.permissions.query({ name: 'clipboard-read',});
//Check permission is granted or not
if (permission.state === 'denied') {
//It's explicitly denied, thus cancelling action
return false;
}
//Get buffer
navigator.clipboard.readText().then(result => {
let buffer = result.toString();
//Get initial element
let current = event.target;
//Get initial length attribute
let maxLength = parseInt(current.getAttribute('maxlength'));
//Loop while the buffer is too large
while (current && maxLength && buffer.length > maxLength) {
//Ensure input value is updated
current.value = buffer.substring(0, maxLength);
//Trigger input event to bubble any bound events
current.dispatchEvent(new Event('input', {
bubbles: true,
cancelable: true,
}));
//Do not spill over if a field is invalid
if (!current.validity.valid) {
return false;
}
//Update buffer value (not the buffer itself)
buffer = buffer.substring(maxLength);
//Get next node
current = nextInput(current);
if (current) {
//Focus to provide visual identification of a switch
current.focus();
//Update maxLength
maxLength = parseInt(current.getAttribute('maxlength'));
}
}
//Check if we still have a valid node
if (current) {
//Dump everything we can from leftovers
current.value = buffer;
//Trigger input event to bubble any bound events
current.dispatchEvent(new Event('input', {
bubbles: true,
cancelable: true,
}));
}
}).catch(err => {
//Most likely user denied request. Check status
navigator.permissions.query({ name: 'clipboard-read',}).then(newPerm => {
if (newPerm.state === 'granted') {
console.log('Failed to read clipboard', err);
} else {
console.log('Request denied by user. Show him some notification to explain why enabling permission may be useful');
}
}).catch(errPerm => {
console.log('Failed to read clipboard', errPerm);
});
});
}
//Find next/previous input
function nextInput(initial, reverse = false)
{
//Get form
let form = initial.form;
//Iterate inputs inside the form. Not using previousElementSibling, because next/previous input may not be a sibling on the same level
if (form) {
let previous;
for (let moveTo of form.querySelectorAll('input')) {
if (reverse) {
//Check if current element in loop is the initial one, meaning
if (moveTo === initial) {
//If previous is not empty - share it. Otherwise - false, since initial input is first in the form
if (previous) {
return previous;
} else {
return false;
}
}
} else {
//If we are moving forward and initial node is the previous one
if (previous === initial) {
return moveTo;
}
}
//Update previous input
previous = moveTo;
}
}
return false;
}

If you are adding input text fields dynamically then you can try this.
This will re-inject the script into the DOM and works Perfectly.
$('body').on('keyup', '#num_1',function(){
if (this.value.length === parseInt(this.attributes["maxlength"].value)) {
$('#num_2').focus();
}
})
$('body').on('keyup','#num_2', function(){
if (this.value.length === parseInt(this.attributes["maxlength"].value)) {
$('#num_3').focus();
}
})
<input type="text" class="form-control" name="number" maxlength="3" id="num_1">
<input type="text" class="form-control" name="number" maxlength="3" id="num_2">
<input type="text" class="form-control" name="number" maxlength="4" id="num_3">

If you're focused on creating card(debit/credit) number input type. Then clean an easily manageable jQuery version as follows:
/*..............................................................................................
* jQuery function for Credit card number input group
......................................................................................................*/
// make container label of input groups, responsible
$('.card-box').on('focus', function(e){
$(this).parent().addClass('focus-form-control');
});
$('.card-box').on('blur', function(e){
$(this).parent().removeClass('focus-form-control');
});
$('.card-box-1').on('keyup', function(e){
e.preventDefault();
var max_length = parseInt($(this).attr('maxLength'));
var _length = parseInt($(this).val().length);
if(_length >= max_length) {
$('.card-box-2').focus().removeAttr('readonly');
$(this).attr('readonly', 'readonly');
}
if(_length <= 0){
return;
}
});
$('.card-box-2').on('keyup', function(e){
e.preventDefault();
var max_length = parseInt($(this).attr('maxLength'));
var _length = parseInt($(this).val().length);
if(_length >= max_length) {
$('.card-box-3').focus().removeAttr('readonly');
$(this).attr('readonly', 'readonly');
}
if(_length <= 0){
$('.card-box-1').focus().removeAttr('readonly');
$(this).attr('readonly', 'readonly');
}
});
$('.card-box-3').on('keyup', function(e){
e.preventDefault();
var max_length = parseInt($(this).attr('maxLength'));
var _length = parseInt($(this).val().length);
if(_length >= max_length) {
$('.card-box-4').focus().removeAttr('readonly');
$(this).attr('readonly', 'readonly');
}
if(_length <= 0){
$('.card-box-2').focus().removeAttr('readonly');
$(this).attr('readonly', 'readonly');
}
});
$('.card-box-4').on('keyup', function(e){
e.preventDefault();
var max_length = parseInt($(this).attr('maxLength'));
var _length = parseInt($(this).val().length);
if(_length >= max_length) {
return;
}
if(_length <= 0){
$('.card-box-3').focus().removeAttr('readonly');
$(this).attr('readonly', 'readonly');
}
});
/*..............................................................................................
* End jQuery function for Credit card number input group
......................................................................................................*/
/* Hide HTML5 Up and Down arrows. */
input[type="number"]::-webkit-outer-spin-button, input[type="number"]::-webkit-inner-spin-button {
-webkit-appearance: none; margin: 0;
}
input[type="number"] { -moz-appearance: textfield; }
.card-box {
width: 20%; display: inline-block; height: 100%; border: none;
}
.focus-form-control {
border-color: #66afe9; outline: 0;-webkit-box-shadow: inset 0 1px 1px rgba(0,0,0,.075), 0 0 8px rgba(102, 175, 233, .6);
box-shadow: inset 0 1px 1px rgba(0,0,0,.075), 0 0 8px rgba(102, 175, 233, .6);
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.0/jquery.min.js"></script>
<div class="form-control" style="padding: 0; max-width: 300px; ">
<input class="card-box card-box-1" type="number" id="CreditCard_CardNumber1" required step="1" minlength="4" maxlength="4" pattern="[0-9]{4}" value="" placeholder="0000"
onClick="this.setSelectionRange(0, this.value.length)" oninput="this.value=this.value.slice(0,this.maxLength||'');this.value=(this.value < 1) ? ('') : this.value;"/>
<input class="card-box card-box-2" type="number" id="CreditCard_CardNumber2" readonly required step="1" minlength="4" maxlength="4" pattern="[0-9]{4}" value="" placeholder="0000"
onClick="this.setSelectionRange(0, this.value.length)" oninput="this.value=this.value.slice(0,this.maxLength||'');this.value=(this.value < 1) ? ('') : this.value;" />
<input class="card-box card-box-3" type="number" id="CreditCard_CardNumber3" readonly required step="1" minlength="4" maxlength="4" pattern="[0-9]{4}" value="" placeholder="0000"
onClick="this.setSelectionRange(0, this.value.length)" oninput="this.value=this.value.slice(0,this.maxLength||'');this.value=(this.value < 1) ? ('') : this.value;" />
<input class="card-box card-box-4" type="number" id="CreditCard_CardNumber4" readonly required step="1" minlength="4" maxlength="4" pattern="[0-9]{4}" value="" placeholder="0000"
onClick="this.setSelectionRange(0, this.value.length)" oninput="this.value=this.value.slice(0,this.maxLength||'');this.value=(this.value < 1) ? ('') : this.value;" />
</div>

Verified Answer have one issue which focus previous field if previous field have valid length
I have Modified Above Answer to fix complete length of previous tag
var container = document.getElementsByClassName("container")[0];
container.onkeyup = function(e) {
var target = e.srcElement || e.target;
var maxLength = parseInt(target.attributes["maxlength"].value, 10);
var myLength = target.value.length;
if (myLength >= maxLength) {
var next = target;
while (next = next.nextElementSibling) {
if (next == null)
break;
if (next.tagName.toLowerCase() === "input") {
next.focus();
break;
}
}
}
// Move to previous field if empty (user pressed backspace)
else if (myLength === 0) {
var previous = target;
// Move to previous field if backspace is pressed
if (code == 8) {
previous = previous.previousElementSibling;
if (previous != null) {
if (previous.tagName.toLowerCase() === "input") {
previous.focus();
}
}
} else {
while (previous = previous.previousElementSibling) {
if (previous == null)
break;
if (previous.tagName.toLowerCase() === "input") {
var mLength = parseInt(previous.attributes["maxlength"].value, 10);
var pMyLength = previous.value.length;
// Move to previous field if it does not have required length
if (mLength == pMyLength) {
break;
} else {
previous.focus();
break;
}
}
}
}
}
}

I think this is a shorter way. As long as you use a specific structure in HTML
const inputHandler = (event) => {
if (event.target.nodeName == "INPUT" && event.target.nextElementSibling != null) {
event.target.nextElementSibling.focus();
}
}
<div class="enter-code">
<input type="text" maxlength="1" #keyup="inputHandler">
<input type="text" maxlength="1" #keyup="inputHandler">
<input type="text" maxlength="1" #keyup="inputHandler">
<input type="text" maxlength="1" #keyup="inputHandler">
</div>

Turn input text to uppercase, only if the checkbox is checked

I have checkbox and input text and I need turn input charaters to uppercase, only when checkbox is checked.
So, if checkbox is not checked and and I type "aa", then check checkbox and type "bb", result should be: "aaBB"
I have this code but this is incorrect, as it turns entire input value to uppercase, when checkbox is checked.
$(document).ready(function() {
$('input').keyup(function() {
if ($("#ch").is(":checked")) {
this.value = this.value.toLocaleUpperCase();
}
});
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<input type="checkbox" id="ch" />
<input type="text" id="myinp" />
http://jsfiddle.net/tqa8p9ub/

You can do this with plain JavaScript using the keypress event and adding the character uppercased or not to the current input value depending on your checkbox state.
Using the keypress event is preferable to using keyup since you can intercept the key before it gets added to the input, which allows you to transform it or not or even discard it. Using keyup however forces you to change the whole input value since the value will already have been added to the input. You may also see a small flicker in this case.
Also you have to prevent the event from finishing executing by calling event.preventDefault(), otherwise the character will be added twice to the input.
You also need to insert the character at the right position using input.selectionStart. Once inserted, you have to increment both input.selectionStart and input.selectionEnd, see this answer for more details.
const checkbox = document.querySelector('#ch');
const input = document.querySelector('#myinp');
input.addEventListener('keypress', event => {
const checked = checkbox.checked;
const char = checkbox.checked ? event.key.toLocaleUpperCase() : event.key;
const pos = input.selectionStart || 0;
input.value = input.value.slice(0, pos) + char + input.value.slice(pos);
input.selectionStart = pos + 1;
input.selectionEnd = pos + 1;
event.preventDefault();
});
<input type="checkbox" id="ch" />
<input type="text" id="myinp" />

Try this -
$(document).ready(function() {
$('input').keyup(function(e) {
if ($("#ch").is(":checked")) {
let lastChar = e.key;
lastChar = lastChar.toUpperCase();
this.value = this.value.substr(0, this.value.length - 1) + lastChar;
}
});
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<input type="checkbox" id="ch" />
<input type="text" id="myinp" />
Live in action - https://jsitor.com/Q0aigCO1j

Temporarily disable an input field if second input field is filled

I'm attempting to disable an input while the user is filling another input. I've managed to disable one of the two inputs while the other input is being filled in.
The problem is that I want the disabled input to ONLY be disabled WHILE the other input is being typed in.
So if the user changes their mind on the 1st input, they can delete what is in the current input which makes the 2nd input available and the 1st disabled.
JS
var inp1 = document.getElementById("input1");
inp1.onchange = function () {
if (this.value != "" || this.value.length > 0) {
document.getElementById("input2").disabled = true;
}
}
HTML
<input type="text" id="input1">
<input type="text" id="input2">

First, I would use input rather than change. Then, you need to set disabled back to false if the input is blank. Your check for whether it's blank is redundant, you just neither either side of your ||, not both. (I'd also use addEventListener rather than assigning to an .onxyz property, so that it plays nicely with others. :-) )
So:
var inp1 = document.getElementById("input1");
inp1.addEventListener("input", function () {
document.getElementById("input2").disabled = this.value != "";
});
<input type="text" id="input1">
<input type="text" id="input2">
...and then of course if you want it to be mutual, the same for input2.

You can achieve this using focus and blur. Below it is done with JQuery.
$(function() {
$('#input1').focus(function(){
$('#input2').prop('disabled', 'disabled');
}).blur(function(){
$('#input2').prop('disabled', '');
});
$('#input2').focus(function(){
$('#input1').prop('disabled', 'disabled');
}).blur(function(){
$('#input1').prop('disabled', '');
});
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<input type="text" id="input1">
<input type="text" id="input2">

How about using keyup?
Like this;
var inp1 = document.getElementById("input1");
var inp2 = document.getElementById("input2");
inp1.onkeyup = function() { inputValidation(this, inp2); }
inp2.onkeyup = function() { inputValidation(this, inp1); }
function inputValidation(origin, lock) {
var response = hasValue(origin.value);
lock.disabled = response;
}
function hasValue(value) {
return value != "" && value.length > 0;
}
https://jsfiddle.net/8o3wwp6s/

Don't make it harder than it is, this is simple.
var one = document.getElementById('one');
var two = document.getElementById('two');
//checks instantly
var checker = setInterval(function() {
if(two.value !== '') {
one.disabled = true;
} else {
//when its clear, it enabled again
one.disabled = false;
}
if(one.value !== '') {
two.disabled = true
} else {
two.disabled = false;
}
}, 30);
<input id="one">
<input id="two">

Number input field exclude range of numbers in middle

In input field how can i exclude range of numbers
e.g. allow user to put value < -5 or value > 5 and not allow anything between -4 to 4?. I am not asking for max or min values
<input type="number" id="input" step="1" />
Thanks

First add excmin and excmax attribute to target element(in this case element with id="input") to values you want.
Then call this function and pass element to this function on page load:
:
function exceptionrange(element)
{
var excmin=parseInt(element.getAttribute("excmin"))-1;
var excmax=parseInt(element.getAttribute("excmax"))+1;
element.onchange=function()
{
if(element.value<excmax&&element.value>excmin)
{
element.value=Math.round((parseInt(element.value)-excmin)/(excmin-excmax))*(excmin-excmax)+excmin;
}
};
}
Now, whenever user enter a value in this range, it will change it to near allowed value when user is done entering number.
So this is how script will look like:
function exceptionrange(element)
{
var excmin=parseInt(element.getAttribute("excmin"))-1;
var excmax=parseInt(element.getAttribute("excmax"))+1;
element.onchange=function()
{
if(element.value<excmax&&element.value>excmin)
{
element.value=Math.round((parseInt(element.value)-excmin)/(excmin-excmax))*(excmin-excmax)+excmin;
}
};
}
window.addEventListener("load",function()
{
var input=document.getElementById("input");
exceptionrange(input);
});
And this is the input element:
<input type="number" id="input" step="1" excmin="-4" excmax="4"/>

I wanted to exclude 2,4,5,7,8,9,10,11 from my Shopify products quantity in input number field so I created the following code for it.
Input Element
<input type="number" id="input"/>
JS code
function exceptionrange(element)
{
var inputValue = 0
element.onchange=function()
{
if(inputValue<element.value){
if(element.value==2)
{
element.value=3;
}
if(element.value==4 || element.value==5)
{
element.value=6;
}
if(element.value==7 || element.value==8 || element.value==9 || element.value==10 || element.value==11)
{
element.value= 12;
}
}
if(inputValue>element.value){
if(element.value==2)
{
element.value=1;
}
if(element.value==4 || element.value==5)
{
element.value=3;
}
if(element.value==7 || element.value==8 || element.value==9 || element.value==10 || element.value==11)
{
element.value= 6;
}
}
inputValue = element.value
};
}
window.addEventListener("load",function()
{
var input=document.getElementById("input");
exceptionrange(input);
});

Focus next input once reaching maxlength value

How can I focus the next input once the previous input has reached its maxlength value?
a: <input type="text" maxlength="5" />
b: <input type="text" maxlength="5" />
c: <input type="text" maxlength="5" />
If a user pastes text that is greater than the maxlength, ideally it should spill into the next input.
jsFiddle: http://jsfiddle.net/4m5fg/1/
I must stress that I do not want to use a plugin, as I'd much rather learn the logic behind this, than use something that already exists. Thanks for understanding.

No jQuery used and is a very clean implementation:
Reads from the maxlength attribute.
Scales to any number of inputs inside of your container.
Automatically finds the next input to focus.
No jQuery.
http://jsfiddle.net/4m5fg/5/
<div class="container">
a: <input type="text" maxlength="5" />
b: <input type="text" maxlength="5" />
c: <input type="text" maxlength="5" />
</div>
..
var container = document.getElementsByClassName("container")[0];
container.onkeyup = function(e) {
var target = e.srcElement || e.target;
var maxLength = parseInt(target.attributes["maxlength"].value, 10);
var myLength = target.value.length;
if (myLength >= maxLength) {
var next = target;
while (next = next.nextElementSibling) {
if (next == null)
break;
if (next.tagName.toLowerCase() === "input") {
next.focus();
break;
}
}
}
// Move to previous field if empty (user pressed backspace)
else if (myLength === 0) {
var previous = target;
while (previous = previous.previousElementSibling) {
if (previous == null)
break;
if (previous.tagName.toLowerCase() === "input") {
previous.focus();
break;
}
}
}
}

You can watch for input in the fields and test its value:
$("input").bind("input", function() {
var $this = $(this);
setTimeout(function() {
if ( $this.val().length >= parseInt($this.attr("maxlength"),10) )
$this.next("input").focus();
},0);
});
Working demo.
The setTimeout is there to ensure the code will only run after the input is completed and the value updated. Binding input ensures most types of input will trigger the event, including key presses, copy/paste (even from mouse) and drag & drop (though in this case, the latter won't work, since the focus was on the draggable, not the droppable).
Note: on some older browsers, you might also need to bind propertychange.
If a user pastes text that is greater than the maxlength, ideally it should spill into the next input.
To do that, you might need to remove the maxlength attribute using JavaScript (to be able to capture the full input), and implement that functionality yourself. I made a small example, relevant parts below:
$("input").each(function() {
var $this = $(this);
$(this).data("maxlength", $this.prop("maxlength"));
$(this).removeAttr("maxlength");
})
This removes the attribute, but saves it in data, so you can access it later.
function spill($this, val) {
var maxlength = $this.data("maxlength");
if ( val.length >= maxlength ) {
$this.val(val.substring(0, maxlength));
var next = $this.next("input").focus();
spill(next, val.substring(maxlength));
}
else
$this.val(val);
}
Here the max length logic is reintroduced in JavaScript, as well as getting the "discarded" part and using it in a recursive call to spill. If there's no next element, the call to data will return undefined and the loop will stop, so the input will be truncated in the last field.

You can use plain JavaScript:
See DEMO.
Check the character length with el.value.length. If it is equal to the maximum value, move to the next field by using focus(). Bind this function to the keyup event with onkeyup so that the function fires every time after the user keys in a character.
var a = document.getElementById("a"),
b = document.getElementById("b"),
c = document.getElementById("c");
a.onkeyup = function() {
if (this.value.length === parseInt(this.attributes["maxlength"].value)) {
b.focus();
}
}
b.onkeyup = function() {
if (this.value.length === parseInt(this.attributes["maxlength"].value)) {
c.focus();
}
}

if you are going to have many fields you can do something like this.
basically on keyup get the length of the input and then compare it to the maxlength, if matches, then focus onto the next input field.
http://jsfiddle.net/btevfik/DVxDA/
$(document).ready(function(){
$('input').keyup(function(){
if(this.value.length==$(this).attr("maxlength")){
$(this).next().focus();
}
});
});

let otp = document.querySelector('#otp-screen');
for(let pin of otp.children) {
pin.onkeyup = function() {
if(pin.nextElementSibling) {
pin.nextElementSibling.focus();
}
}
}
<div class="otp-screen" id="otp-screen">
<input type="text" placeholder="0" maxlength="1"/>
<input type="text" placeholder="0" maxlength="1"/>
<input type="text" placeholder="0" maxlength="1"/>
<input type="text" placeholder="0" maxlength="1"/>
</div>

Updated btevfik code, Onkeyup or onkeydown will create issue as you won't be able to delete the previous input on tab navigation. It will be tough to edit or change the text inside the input box as it will be limited to maxlength. So we can use oninput event to achieve the task.
DEMO
HTML
<ul>
<li>a: <input type="text" maxlength="5" /></li>
<li>b: <input type="text" maxlength="3" /></li>
<li>c: <input type="text" maxlength="5" /></li>
<li>d: <input type="text" maxlength="3" /></li>
<li>e: <input type="text" maxlength="6" /></li>
<li>f: <input type="text" maxlength="10" /></li>
<li>g: <input type="text" maxlength="7" /></li>
</ul>
Javascript
$(document).ready(function(){
$('input').on("input", function(){
if($(this).val().length==$(this).attr("maxlength")){
$(this).next().focus();
}
});
});
CSS
ul {list-style-type:none;}
li {padding:5px 5px;}

Other answers do give some idea how this can be implemented, but I find that they do not consider some minor things among which are:
The fact, that you do not want to auto-focus any elements across whole page, but rather within specific form.
Input elements can be wrapped in some other elements (for example I wrap them in span or div to allow floating labels through CSS, and I've seen forms that use table to for structure).
Validity of the field, when spilling over or moving to next one automatically.
Input events when spilling over.
Cursor position when returning to previous field (it looks like it can be saved by browser, thus backspacing can focus not in the end of the field, but, for example, in the middle).
Below code is trying to account to all of this, at least. Most of it can be tested on codepen: paste-spilling does not work there, looks like because of Clipboard API (other codepens with it do not work for me either).
Let me know if anything is unclear in the code, I'll update my answer and the code. If you find some edge case that is not covered - let me know as well.
For paste-spilling test using form from codepen, you can use something like this: 123456789123456789012345678903454353434534
Video sample of how it works in a more "live" envitonment on youtube
//List of input types, that are "textual" by default, thus can be tracked through keypress and paste events. In essence,
// these are types, that support maxlength attribute
const textInputTypes = ['email', 'password', 'search', 'tel', 'text', 'url', ];
formInit();
//Add listeners
function formInit()
{
document.querySelectorAll('form input').forEach((item)=>{
if (textInputTypes.includes(item.type)) {
//Somehow backspace can be tracked only on keydown, not keypress
item.addEventListener('keydown', inputBackSpace);
if (item.getAttribute('maxlength')) {
item.addEventListener('input', autoNext);
item.addEventListener('change', autoNext);
item.addEventListener('paste', pasteSplit);
}
}
});
}
//Track backspace and focus previous input field, if input is empty, when it's pressed
function inputBackSpace(event)
{
let current = event.target;
if ((event.keyCode || event.charCode || 0) === 8 && !current.value) {
let moveTo = nextInput(current, true);
if (moveTo) {
moveTo.focus();
//Ensure, that cursor ends up at the end of the previous field
moveTo.selectionStart = moveTo.selectionEnd = moveTo.value.length;
}
}
}
//Focus next field, if current is filled to the brim and valid
function autoNext(event)
{
let current = event.target;
//Get length attribute
let maxLength = parseInt(current.getAttribute('maxlength'));
//Check it against value length
if (maxLength && current.value.length === maxLength && current.validity.valid) {
let moveTo = nextInput(current, false);
if (moveTo) {
moveTo.focus();
}
}
}
async function pasteSplit(event)
{
let permission = await navigator.permissions.query({ name: 'clipboard-read',});
//Check permission is granted or not
if (permission.state === 'denied') {
//It's explicitly denied, thus cancelling action
return false;
}
//Get buffer
navigator.clipboard.readText().then(result => {
let buffer = result.toString();
//Get initial element
let current = event.target;
//Get initial length attribute
let maxLength = parseInt(current.getAttribute('maxlength'));
//Loop while the buffer is too large
while (current && maxLength && buffer.length > maxLength) {
//Ensure input value is updated
current.value = buffer.substring(0, maxLength);
//Trigger input event to bubble any bound events
current.dispatchEvent(new Event('input', {
bubbles: true,
cancelable: true,
}));
//Do not spill over if a field is invalid
if (!current.validity.valid) {
return false;
}
//Update buffer value (not the buffer itself)
buffer = buffer.substring(maxLength);
//Get next node
current = nextInput(current);
if (current) {
//Focus to provide visual identification of a switch
current.focus();
//Update maxLength
maxLength = parseInt(current.getAttribute('maxlength'));
}
}
//Check if we still have a valid node
if (current) {
//Dump everything we can from leftovers
current.value = buffer;
//Trigger input event to bubble any bound events
current.dispatchEvent(new Event('input', {
bubbles: true,
cancelable: true,
}));
}
}).catch(err => {
//Most likely user denied request. Check status
navigator.permissions.query({ name: 'clipboard-read',}).then(newPerm => {
if (newPerm.state === 'granted') {
console.log('Failed to read clipboard', err);
} else {
console.log('Request denied by user. Show him some notification to explain why enabling permission may be useful');
}
}).catch(errPerm => {
console.log('Failed to read clipboard', errPerm);
});
});
}
//Find next/previous input
function nextInput(initial, reverse = false)
{
//Get form
let form = initial.form;
//Iterate inputs inside the form. Not using previousElementSibling, because next/previous input may not be a sibling on the same level
if (form) {
let previous;
for (let moveTo of form.querySelectorAll('input')) {
if (reverse) {
//Check if current element in loop is the initial one, meaning
if (moveTo === initial) {
//If previous is not empty - share it. Otherwise - false, since initial input is first in the form
if (previous) {
return previous;
} else {
return false;
}
}
} else {
//If we are moving forward and initial node is the previous one
if (previous === initial) {
return moveTo;
}
}
//Update previous input
previous = moveTo;
}
}
return false;
}

If you are adding input text fields dynamically then you can try this.
This will re-inject the script into the DOM and works Perfectly.
$('body').on('keyup', '#num_1',function(){
if (this.value.length === parseInt(this.attributes["maxlength"].value)) {
$('#num_2').focus();
}
})
$('body').on('keyup','#num_2', function(){
if (this.value.length === parseInt(this.attributes["maxlength"].value)) {
$('#num_3').focus();
}
})
<input type="text" class="form-control" name="number" maxlength="3" id="num_1">
<input type="text" class="form-control" name="number" maxlength="3" id="num_2">
<input type="text" class="form-control" name="number" maxlength="4" id="num_3">

If you're focused on creating card(debit/credit) number input type. Then clean an easily manageable jQuery version as follows:
/*..............................................................................................
* jQuery function for Credit card number input group
......................................................................................................*/
// make container label of input groups, responsible
$('.card-box').on('focus', function(e){
$(this).parent().addClass('focus-form-control');
});
$('.card-box').on('blur', function(e){
$(this).parent().removeClass('focus-form-control');
});
$('.card-box-1').on('keyup', function(e){
e.preventDefault();
var max_length = parseInt($(this).attr('maxLength'));
var _length = parseInt($(this).val().length);
if(_length >= max_length) {
$('.card-box-2').focus().removeAttr('readonly');
$(this).attr('readonly', 'readonly');
}
if(_length <= 0){
return;
}
});
$('.card-box-2').on('keyup', function(e){
e.preventDefault();
var max_length = parseInt($(this).attr('maxLength'));
var _length = parseInt($(this).val().length);
if(_length >= max_length) {
$('.card-box-3').focus().removeAttr('readonly');
$(this).attr('readonly', 'readonly');
}
if(_length <= 0){
$('.card-box-1').focus().removeAttr('readonly');
$(this).attr('readonly', 'readonly');
}
});
$('.card-box-3').on('keyup', function(e){
e.preventDefault();
var max_length = parseInt($(this).attr('maxLength'));
var _length = parseInt($(this).val().length);
if(_length >= max_length) {
$('.card-box-4').focus().removeAttr('readonly');
$(this).attr('readonly', 'readonly');
}
if(_length <= 0){
$('.card-box-2').focus().removeAttr('readonly');
$(this).attr('readonly', 'readonly');
}
});
$('.card-box-4').on('keyup', function(e){
e.preventDefault();
var max_length = parseInt($(this).attr('maxLength'));
var _length = parseInt($(this).val().length);
if(_length >= max_length) {
return;
}
if(_length <= 0){
$('.card-box-3').focus().removeAttr('readonly');
$(this).attr('readonly', 'readonly');
}
});
/*..............................................................................................
* End jQuery function for Credit card number input group
......................................................................................................*/
/* Hide HTML5 Up and Down arrows. */
input[type="number"]::-webkit-outer-spin-button, input[type="number"]::-webkit-inner-spin-button {
-webkit-appearance: none; margin: 0;
}
input[type="number"] { -moz-appearance: textfield; }
.card-box {
width: 20%; display: inline-block; height: 100%; border: none;
}
.focus-form-control {
border-color: #66afe9; outline: 0;-webkit-box-shadow: inset 0 1px 1px rgba(0,0,0,.075), 0 0 8px rgba(102, 175, 233, .6);
box-shadow: inset 0 1px 1px rgba(0,0,0,.075), 0 0 8px rgba(102, 175, 233, .6);
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.0/jquery.min.js"></script>
<div class="form-control" style="padding: 0; max-width: 300px; ">
<input class="card-box card-box-1" type="number" id="CreditCard_CardNumber1" required step="1" minlength="4" maxlength="4" pattern="[0-9]{4}" value="" placeholder="0000"
onClick="this.setSelectionRange(0, this.value.length)" oninput="this.value=this.value.slice(0,this.maxLength||'');this.value=(this.value < 1) ? ('') : this.value;"/>
<input class="card-box card-box-2" type="number" id="CreditCard_CardNumber2" readonly required step="1" minlength="4" maxlength="4" pattern="[0-9]{4}" value="" placeholder="0000"
onClick="this.setSelectionRange(0, this.value.length)" oninput="this.value=this.value.slice(0,this.maxLength||'');this.value=(this.value < 1) ? ('') : this.value;" />
<input class="card-box card-box-3" type="number" id="CreditCard_CardNumber3" readonly required step="1" minlength="4" maxlength="4" pattern="[0-9]{4}" value="" placeholder="0000"
onClick="this.setSelectionRange(0, this.value.length)" oninput="this.value=this.value.slice(0,this.maxLength||'');this.value=(this.value < 1) ? ('') : this.value;" />
<input class="card-box card-box-4" type="number" id="CreditCard_CardNumber4" readonly required step="1" minlength="4" maxlength="4" pattern="[0-9]{4}" value="" placeholder="0000"
onClick="this.setSelectionRange(0, this.value.length)" oninput="this.value=this.value.slice(0,this.maxLength||'');this.value=(this.value < 1) ? ('') : this.value;" />
</div>

Verified Answer have one issue which focus previous field if previous field have valid length
I have Modified Above Answer to fix complete length of previous tag
var container = document.getElementsByClassName("container")[0];
container.onkeyup = function(e) {
var target = e.srcElement || e.target;
var maxLength = parseInt(target.attributes["maxlength"].value, 10);
var myLength = target.value.length;
if (myLength >= maxLength) {
var next = target;
while (next = next.nextElementSibling) {
if (next == null)
break;
if (next.tagName.toLowerCase() === "input") {
next.focus();
break;
}
}
}
// Move to previous field if empty (user pressed backspace)
else if (myLength === 0) {
var previous = target;
// Move to previous field if backspace is pressed
if (code == 8) {
previous = previous.previousElementSibling;
if (previous != null) {
if (previous.tagName.toLowerCase() === "input") {
previous.focus();
}
}
} else {
while (previous = previous.previousElementSibling) {
if (previous == null)
break;
if (previous.tagName.toLowerCase() === "input") {
var mLength = parseInt(previous.attributes["maxlength"].value, 10);
var pMyLength = previous.value.length;
// Move to previous field if it does not have required length
if (mLength == pMyLength) {
break;
} else {
previous.focus();
break;
}
}
}
}
}
}

I think this is a shorter way. As long as you use a specific structure in HTML
const inputHandler = (event) => {
if (event.target.nodeName == "INPUT" && event.target.nextElementSibling != null) {
event.target.nextElementSibling.focus();
}
}
<div class="enter-code">
<input type="text" maxlength="1" #keyup="inputHandler">
<input type="text" maxlength="1" #keyup="inputHandler">
<input type="text" maxlength="1" #keyup="inputHandler">
<input type="text" maxlength="1" #keyup="inputHandler">
</div>