I've got a textarea with onkeypress function call, and i would like to check if the numbers of rows are more than 10: if they are, i would't like to write the character. How can i "stop" the writing after the function check?
<textarea id="textAr" maxlength="350" rows="6" onkeypress="check(this)"></textarea>
function checkLines(textArea){
var text = textArea.value;
var linesNumber = text.split("\n").length;
// alert("number of rows is: " + linesNumber);
if(linesNumber > 10){
???
}
}
To stop a character being written, you can use the event.preventDefault() method. We can do this by adding an event listener to the element in place of an onkeypress attribute.
function checkLines(event){
var text = this.value;
var linesNumber = text.split("\n").length;
// alert("number of rows is: " + linesNumber);
if(linesNumber > 10){
event.preventDefault();
}
}
document.querySelector("#textAr").addEventListener("keypress", checkLines);
You can also use event.key to fetch the key being pressed. This would allow you to only prevent new lines with the enter key ("Enter").
if(linesNumber > 10 && event.key == "Enter"){
event.preventDefault();
}
Related
I have a calculator I'm working on and came across a problem. To combat so that users can't leave a field blank, I'm forcing a zero if the field is left empty. That's all fine, but the problem is that when the text in the field is deleted to remove the zero and enter a new number, it automatically enters zero so my new number looks like this: 05
How do i run a replace where if there is more than 2 places in the number and the first number is zero, replace the zero? Here's the code i'm using for my calculator.
$(function(){
calculate();
$('.input').keypress(function (e) {
//if the letter is not digit then display error and don't type anything
if (e.which != 8 && e.which != 0 && (e.which < 48 || e.which > 57)) {
return false;
}
});
$('.input').on('keyup',function(){
if($(this).val()==''){
$(this).val('0');
}
calculate();
});
});
function calculate(){
var d6 = parseFloat(($('#d6').val()).replace(/,/g,''));
var d20 = parseFloat(($('#d20').val()).replace(/,/g,''));
var b20 = d6;
var e20 = parseFloat(($('#e20').val()).replace(/,/g,''));
var f20 = d20*e20;
var f22 = b20/f20;
var f23 = (52-f22)*f20;
$('#f20').html(formatCurrency(f20));
$('#f22').html(f22.toFixed(2));
$('#f23').html(formatCurrency(f23));
}
function formatCurrency(x) {
return '$'+x.toString().replace(/\B(?=(?:\d{3})+(?!\d))/g, ",");
}
If you are essentially trying to turn it into a formatted number you could try type coercion:
'' + new Number('') // "0"
'' + new Number('0') // "0"
'' + new Number('05') // "5"
'' + new Number('0000.2') // "0.2"
Change the zeroing code to use the blur() event, i.e when the field loses focus.
$('.input').blur(function(){
if($(this).val()=='')
{
$(this).val('0');
}
});
I'm assuming that the text is removed from pressing the backspace key.
If that is the case then you keyup handler would fire when you backspace on the zero, which would detect no input, then add the zero.
First of all, you are doing it a hard way. And try this... if the user clicks on the input then it will be cleared and the user can write whatever number he wants...
$( ".input" ).focus(function() {
(this).val('');
});
In case you are using an HTML5 form you can avoid that piece of code like this:
<input type="number" placeholder="Type a number" required>
The required attribute is a boolean attribute.
When present, it specifies that an input field must be filled out.
Instead of using keyup and keypress event for checking and replacing blank to zero, use change event.
$(function(){
calculate();
$('.input').keypress(function (e) {
//if the letter is not digit then display error and don't type anything
if (e.which != 8 && e.which != 0 && (e.which < 48 || e.which > 57)) {
return false;
}
});
$('.input').on('keyup',function(){
calculate();
});
$('.input').on('change',function(){
if($(this).val()==''){
$(this).val('0');
}
});
});
function calculate(){
var d6Val = ($('#d6').val() !== "")? $('#d6').val() : '0';
var d20Val = ($('#d20').val() !== "")? $('#d20').val() : '0';
var e20Val = ($('#e20').val() !== "")? $('#e20').val() : '0';
var d6 = parseFloat((d6Val).replace(/,/g,''));
var d20 = parseFloat((d20Val).replace(/,/g,''));
var b20 = d6;
var e20 = parseFloat((e20Val).replace(/,/g,''));
var f20 = d20*e20;
var f22 = b20/f20;
var f23 = (52-f22)*f20;
$('#f20').html(formatCurrency(f20));
$('#f22').html(f22.toFixed(2));
$('#f23').html(formatCurrency(f23));
}
function formatCurrency(x) {
return '$'+x.toString().replace(/\B(?=(?:\d{3})+(?!\d))/g, ",");
}
One more thing. Change event only fires when you focus-out from that input.
Please let me know if you will face any issue.
I have the following code: http://jsfiddle.net/ntywf/1987/
$(document).ready(function () {
$('input').keyup(function() {
var $th = $(this);
$th.val($th.val().replace(/[-]/g, function(str) {
//alert('You typed " ' + str + ' ".\n\nPlease use only letters and numbers.');
return '';
}));
});
});
what I want is to remove the "-" sign off when it is inserted. what happens is that the cursor is always the last decimal home. I just want this code not to let the user enter negative numbers. How can I do this? (the problem is to move the cursor within the input, since it is always sent to the last character)
You can use a KeyCode (Link) to verify what key you pressed, and use replace to remove it:
$('input').keyup(function(e) {
var code = e.keyCode || e.which;
if(code == 109 || code == 189) { //Enter keycode
//Do something
var valor = $(this).val();
$(this).val(valor.replace(/[-]/g, ''))
}
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<input type="text"/>
Here what I have tried.
JS
$('input').keyup(function() {
var $th = $(this).val();
$th = $th.replace(/[-]/g, "");
$(this).val($th)
console.log( $(this).val());
});
It will remove - sign from data.
This should solve your problem
What I have done is:
I have used the inbuilt HTML input field method setSelectionRange(), which sets the start and end positions of the current text selection in an element. (From MDN)
MDN Reference : https://developer.mozilla.org/en-US/docs/Web/API/HTMLInputElement/setSelectionRange
JS Code:
$(document).ready(function () {
$('input').keyup(function() {
var $th = $(this);
$th.val( $th.val().replace(/[-]/g, function(str) {
//alert('You typed " ' + str + ' ".\n\nPlease use only letters and numbers.');
return '';
} ) );
$('input')[0].setSelectionRange(0, 0); //this method sets the range to zero text starting from 0 index to 0 index
});
});
JSFiddle: http://jsfiddle.net/dreamweiver/ntywf/1998/
Use type = "numeric" and min="0" This way you can prevent your text-field from accepting alphabets as well. min=0 will always make sure that it will never accept -ve value.
<input type="number" min="0"/>
JSFIDDLE DEMO will be helpful to you.
I am having a problem validating a textbox to not allow spacing. When the user enters a space I would like it to display an alert message and then clear the textbox, but the textbox doesn't clear. This is what I have so far.
function ValidateSpace () {
var SerNum = document.getElementById("txtbox1")
if (event.keyCode == 32) {
alert("This field may contain no spaces.");
document.getElementById ("txtbox1").value=""
}
}
I have users trying to put multiple entries in this space but it should only accept one. The textbox is for inventory purposes so it would change the nature of the data if I were to remove spaces
I suppose that you have to bind keyDown event on textbox
try this jquery code to remove live the spaces
$("#IdOfTheTextBox").on("keydown", function (e) {
return e.which !== 32;
});
If you can't use jquery try with this javascript function (onkeypress event of textbox)
function NoSpace() {
if (event.keyCode == 32) {
event.returnValue = false;
return false;
}
}
if you want to remove spaces after the input you can do this
var noSpaces = document.getElementById("txtbox1").value.replace(/\s/g, "");
I'm trying to validate a character to make sure it's a letter (not a number, symbol, etc.) BEFORE it's allowed to be entered into the form field. How can I do that with JavaScript?
Here is something I tried:
<script type="text/javascript">
function checkTest() {
var letterValue = document.forms[0].test.value;
var letterCheck = /[a-z]/i;
var letterTest = letterValue.test(letterCheck);
}
</script>
<html>
<body>
<form>
<input type="text" name="test" onkeypress="checkTest();"/>
</form>
</body>
</html>
This code will check the string of the value. I've tried using var letterLeng= letterValue.length and then using var letterChar = letterValue.charAt(letterLeng) or even var letterChar = letterValue.charAt(letterLeng - 1) and all to no avail. Any advice would be much appreciated.
Ask the event for the key that was pressed then test it:
function checkTest(event) {
event = event || window.event;
if (!/[A-Za-z]/.test(String.fromCharCode(event.keyCode || event.which))) {
if (event.preventDefault)
event.preventDefault();
else
event.returnValue = false;
}
}
<input type="text" name="test" onkeypress="checkTest(event);"/>
I like Alex K's answer, but I could not get the 'onkeypress' handler to work so I tried something using Jquery. It doesn't keep the bad letters from appearing briefly, but it does keep them from being entered.
It uses the 'keyup' event, which actually makes checking for the key code much easier in this instance since you want to limit it to [a-zA-Z]
$("#myinput").on("keyup", function (e) {
// Ignore the shift key.
if (e.keyCode === 16) {
return true;
}
if ((e.keyCode < 65 || e.keyCode > 90)) {
var str = $("#myinput").val();
$("#myinput").val(str.slice(0, str.length - 1));
}
});
The working fiddle is here: http://jsfiddle.net/yaa9snce/
What you are looking for is the onkeypress event.
<input type="text" onkeypress="myFunction()">
<script>
function myFunction() {
alert("You pressed a key inside the input field");
}
</script>
I would like to have an input that would change to upper case on keyup. So I attach a simple event on keyup.
HTML
<input id="test"/>
Javascript (with jQuery)
$("#test").keyup(function(){
this.value = this.value.toUpperCase();
});
But I found that in Chrome and IE, when you push left arrow, the cursor automatically move to end. I notice that I should detect if the input is letter only. Should I use keycode range or regexp for detection?
Example: http://jsbin.com/omope3
Or you can use the following (this is probably faster and more elegant):
<input style="text-transform: uppercase" type='text'></input>
But that sends the as-typed value back in the form data, so use either of the following to store it as all-caps in the database:
MySQL: UPPER(str)
PHP: strtoupper()
Another solution, if you use the text-transform: uppercase; css property:
<input id='test' style='text-transform: uppercase;' type='text'></input>
And with jQuery help you choose the blur event:
$("#test").blur(function(){
this.value = this.value.toUpperCase();
});
With this solution, you don't have to upper the database fields, you can use the cursor for movement and the user can insert/rewrite the text in the input field.
Use this:
<input onkeyup="MakeMeUpper(this)" type="text"/>
And in your JS Code Part put:
function MakeMeUpper(f, e){
var actualValue = f.value;
var upperValue = f.value.toUpperCase();
if( actValue != upperValue){
f.value = upperValue;
}
}
This code won't change the text if the user entered something that is not text (left or right arrow).
Yeah, looks like some browsers move the cursor to the end when the value gets updated. You could do this:
$("#test").keyup(function(){
var upper = this.value.toUpperCase();
if (this.value != upper)
this.value = upper;
});
which will only change the value if it needs to be changed. However, that still leaves you with the problem that if you type abd, move left, hit c to get abcd, the cursor will still get moved to the end.
Javascript (with jQuery)
$("#test").keyup(function(){
$(this).val($(this).val().toUpperCase());
});
var str = $(this).val();
if (evt.keyCode != 37 && evt.keyCode != 39)
{
str = str.toLowerCase().replace(/\b[a-z]/g, function(letter) {
return letter.toUpperCase();
});
$(this).val(str);
}
You probably want to look at keyCode in your keyup function.
var UP_ARROW = 38,
DOWN_ARROW = 40;
$('#test').keyup(function(evt){
if (evt.keyCode == UP_ARROW)
{
this.value = this.value.toUpperCase();
}
if (evt.keyCode == DOWN_ARROW)
{
this.value = this.value.toLowerCase();
}
});