Javascript - enabling button when input is filled - javascript

I want to enable my button, when input is filled. I want to do it in pure Javascript.
My code example in HTML:
<form action="sent.php" method="post" name="frm">
<input type="text" name="name_input" id="name" onkeyup="myFunction()"><br>
<button type="submit" class="button button-dark" id="send">Send message</button>
</form>
And Javascript:
document.addEventListener("DOMContentLoaded", function(event) {
document.getElementById('send').disabled = "true";
function myFunction() {
var nameInput = document.getElementById('name').value;
if (!nameInput === "") {
document.getElementById('send').disabled = "false";
}
}
});
I don't know why my button is not changing to enable state after filling something in input. I have tried diffrent ways to do it, but it's still not working.
Please help.

An input element in HTML is enabled only when the disabled attribute is not present.
In your case disabled is always present in your element, it's just that it has a "false" or a "true" value - but this is meaningless according to the specs (http://www.w3schools.com/tags/att_input_disabled.asp)
So you need to remove it altogether:
document.getElementById('send').removeAttribute('disabled')

The problem with your code is that myFunction() isn't available because you defined it in the eventlistener for click.
Complete refactored code answer:
HTML
<form action="sent.php" method="post" name="frm">
<input type="text" name="name_input" id="name">
<br>
<button type="submit" class="button button-dark" id="send" disabled>Send message</button>
</form>
JS
document.getElementById("name").addEventListener("keyup", function() {
var nameInput = document.getElementById('name').value;
if (nameInput != "") {
document.getElementById('send').removeAttribute("disabled");
} else {
document.getElementById('send').setAttribute("disabled", null);
}
});

Try this one it will work for you
function myFunction() {
document.getElementById('send').disabled = true;
var nameInput = document.getElementById('name').value;
if (nameInput != "") {
alert("Empty");
document.getElementById('send').disabled = false;
}
}
if you want to check the input should not be contain number then we can use isNaN() function, it will return true if number is not number otherwise return false

Your code is almost correct but you have defined myFunction inside a block, so input is not able to find myFunction() inside onkeyup="myFunction()"
so just keep the same outside of DOMContentLoaded event
see working demo
document.addEventListener("DOMContentLoaded", function(event) {
document.getElementById('send').disabled = "true";
});
function myFunction() {
var nameInput = document.getElementById('name').value;
console.log(nameInput);
if (nameInput === "") {
document.getElementById('send').disabled = true;
} else {
document.getElementById('send').disabled = false;
}
}

Related

How do I compare user input to a variable?

I don't know how to make this work. Does anyone know how to fix this? I have tried multiple different solutions, but they don't work
function submit() {
var user = "test";
if (document.getElementById('#user').input = user) {
//what I need help on
}
}
function openForm() {
document.getElementById("myForm").style.display = "block";
}
function closeForm() {
document.getElementById("myForm").style.display = "none";
}
<button class="open-button" onclick="openForm()">Open Form</button>
<div class="form-popup" id="myForm">
<form action="#" class="form-container">
<h1>Login</h1>
<label for="username"><b>username</b></label>
<input type="text" placeholder="username" id="username" name="username" required>
<button type="submit" onclick="submit()" class="btn">Login</button>
// And here
<button type="button" class="btn cancel" onclick="closeForm()">Close</button>
</form>
</div>
First, where is user input element, that you mentioned in JavaScript, there is no input with id user, only one input with id username exist, use that and hashtag is not used for ids in document.getElementById
replace
document.getElementById('#user')
to
document.getElementById('username') // use username and remove the hashtag (#)
Secondly, use value instead of input
document.getElementById('username').value
Returns the value (text) of the input element
Lastly, use == or === operators in statements not = in JavaScript.
Example
if (document.getElementById('username').value === user) { // Replaced = with ===
//what I need help on
}
Full JavaScript Code
function submit() {
var user = "test";
if (document.getElementById('username').value === user) {
//what I need help on
}
}
function openForm() {
document.getElementById("myForm").style.display = "block";
}
function closeForm() {
document.getElementById("myForm").style.display = "none";
}
Use this instead
if(document.getElementById('#user').value == user)
I'd suggest you to store the input element in a variable first to dry your code ;)
I see you got the wrong username id, try my code below:
function submit() {
var user = "test";
if (document.getElementById('#username').value == user) {
//what I need help on
}
}

Enable Disabled Button if Input is not empty

I have one simple form which have two fields called first name with id fname and email field with email. I have submit button with id called submit-btn.
I have disabled submit button using javascript like this
document.getElementById("submit-btn").disabled = true;
Now I am looking for allow submit if both of my fields are filled.
My full javascript is like this
<script type="text/javascript">
document.getElementById("submit-btn").disabled = true;
document.getElementById("submit-btn").onclick = function(){
window.open("https://google.com",'_blank');
}
</script>
I am learning javascript and does not know how I can do it. Let me know if someone here can help me for same.
Thanks!
Id propose something like this
Use a block, which encapsulates the names of variables and functions inside the block scope
Make small functions, which do just one thing
Prefer addEventListener over onclick or onanything
There are two types of events you could use on the inputs: input and change. input will react on every keystroke, check will only react, if you blur the input element
I added a check for validity to the email field with checkValidity method
{
const btn = document.getElementById("submit-btn");
const fname = document.getElementById("fname");
const email = document.getElementById("email");
deactivate()
function activate() {
btn.disabled = false;
}
function deactivate() {
btn.disabled = true;
}
function check() {
if (fname.value != '' && email.value != '' && email.checkValidity()) {
activate()
} else {
deactivate()
}
}
btn.addEventListener('click', function(e) {
alert('submit')
})
fname.addEventListener('input', check)
email.addEventListener('input', check)
}
<form>
<input type="text" name="" id="fname">
<input type="email" name="" id="email">
<input type="submit" id="submit-btn" value="Submit">
</form>
This is the simplest solution I can imagine:
myForm.oninput = () => {
btn.disabled = fname.value == '' || email.value == '' || !email.checkValidity();
}
<form id="myForm">
<input type="text" name="" id="fname">
<input type="email" name="" id="email">
<input type="submit" id="btn" value="Submit" disabled>
</form>
Personally, I prefer to use regex to check the e-mail, instead of checkValidity(). Something like this:
/^[\w\-\.\+]+\#[a-zA-Z0-9\.\-]+\.[a-zA-z0-9]{2,4}$/.test(email.value);

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">

Validation on input field using javascript

I wants to check, if entered field's value is valid or not using onchange before submitting the page. I have written like below.It validates well.But how to activate 'NEXT' button when there is no error on input entries.
<div><input type="text" name="your_name" id="your_name" onchange = "validate_Name(this,1,4)" />
<span id="your_name-error" class="signup-error">*</span>
</div>
<div><input type="text" name="your_addr" id="your_addr" onchange = "validate_Name(this,1,4)" />
<span id="your_addr-error" class="signup-error">*</span>
</div>
<input class="btnAction" type="button" name="next" id="next" value="Next" style="display:none;">
<script type="text/javascript" src="../inc/validate_js.js"></script>
<script>
$(document).ready(function() {
$("#next").click(function() {
var output = validate(); //return true if no error
if (output) {
var current = $(".active"); //activating NEXT button
} else {
alert("Please correct the fields.");
}
});
}
function validate() {
//What should write here?I want to analyse the validate_js.js value here.
}
</script>
Inside validate_js.js
function validate_Name(inputVal, minLeng, maxLeng) {
if (inputVal.value.length > maxLeng) {
inputVal.style.background = "red";
inputVal.nextElementSibling.innerHTML = "<br>Max Characters:" + maxLeng;
} else if (!(tBox.value.match(letters))) {
inputVal.style.background = "red";
inputVal.nextElementSibling.innerHTML = "<br>Use only a-zA-Z0-9_ ";
} else {
inputVal.style.background = "white";
inputVal.nextElementSibling.innerHTML = "";
}
}
If by "activating" you want to make it visible, you can call $('#next').show().
However if you want to simulate a click on it, with jQuery you can simply call $('#next').click() or $('#next').trigger('click') as described here. Also, you might want to put everything in a form and programmatically submit the form when the input passes validation.
You could possibly trigger the change event for each field so it validates each one again.
eg.
function validate() {
$("#your_name").trigger('change');
$("#your_addr").trigger('change');
}

Clearing textfield value

I'm trying to clear the textfield in html using javscript if the given condition is met. For ex:- if the user types awesome in textfield then it should reset the textfield (no blank space nothing).
<html>
<input type="text" id="real" onkeypress="blank()" placeholder="tempo"/><br>
<script>
function blank(){
if(document.getElementById('real').value=="awesome"){
real.value='';
}
}
</script>
</html>
Here real is undefined, so instead of
...
real.value = '';
...
do this
...
document.getElementById('real').value = '';
...
Use variable real to store input element and use onkeyup event:
function blank() {
var real = document.getElementById('real');
if (real.value == "awesome") {
real.value = '';
}
}
<input type="text" id="real" onkeyup="blank()" placeholder="tempo" />
<br>
Another good example would be:
document.addEventListener('DOMContentLoaded', function() {
var real = document.getElementById('real');
real.addEventListener('keyup', blank, false);
}, false)
function blank() {
if (this.value === "awesome") {
this.value = '';
}
}
<input type="text" id="real" placeholder="tempo" />
<br>
Change the line
real.value=''
to
document.getElementById('real').value = '';
You can't just say "real.value" because javascript doesn't know what "real" is.
<html>
<input type="text" id="real" onkeypress="blank()" placeholder="tempo"/><br>
<script>
function blank(){
var real = document.getElementById('real');
if(real.value=="awesome"){
real.value='';
}
}
</script>
</html>
You where facing issue with input event "onkeypress" if change the event and use "onkeyup"
issue will be resolved.
<html>
<script>
function blank() {
var real = document.getElementById('real');
if (real.value == "awesome") {
real.value = '';
}
}
</script>
<input type="text" id="real" onkeyup="blank()" placeholder="tempo"/><br>
</html>

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