I wrote a piece of code which will only accept numeric value as key event. It should only accept 0-9 and backspace. But it also allows forward slash as input.
element.addEventListener('keypress',function(event){
var charcodeAcceptable=[47,48,49,50,51,52,53,54,55,56,57,8];
if (window.event) {
var charCode = window.event.keyCode;
}
else if (event) {
var charCode = event.which;
}
if(charcodeAcceptable.indexOf(charCode)==-1){
event.preventDefault();
}
});
The ASCII code for the forward slash / is 47, therefore your indexOf returns 0 and not -1.
After my orginal response quoted below, and based on the comment left by #t.niese I have created an updated pen.
http://codepen.io/ballerton/pen/PzOdxW
Essentialy, use event.key to get the value of the key press and then test against allowed values:
element.addEventListener('keypress',function(event){
var charcodeAcceptable=['1','2','3','4','5','6','7','8','9','0','Backspace'];
if (window.event) {
var charCode = window.event.key;
}
else if (event) {
var charCode = event.key;
}
if(charcodeAcceptable.indexOf(charCode)==-1){
event.preventDefault();
}
});
I have modified the code to use event.keyCode and it works as
expected.
http://codepen.io/ballerton/pen/vKWzRO
element.addEventListener('keypress',function(event){
var charcodeAcceptable=[47,48,49,50,51,52,53,54,55,56,57,8];
if (window.event) {
var charCode = window.event.keyCode;
}
else if (event) {
var charCode = event.keyCode;
}
if(charcodeAcceptable.indexOf(charCode)==-1){
event.preventDefault();
}
});
original pen by Chris Coyier
see comment by #t.niese
With regard to the test itself, is it important t test to see if it is
a window event?
If not could you not just use:
element.addEventListener('keypress',function(event){
var charcodeAcceptable=[47,48,49,50,51,52,53,54,55,56,57,8];
if(charcodeAcceptable.indexOf(event.keyCode)==-1){
event.preventDefault();
}
});
How to disable special characters from paste in a textbox?
Im using a onkeypress event handler
function disableOtherChar(evt) {
var charCode;
charCode = (evt.which) ? evt.which : evt.keyCode;
var ctrl;
ctrl = (document.all) ? event.ctrlKey : evt.modifiers & Event.CONTROL_MASK;
if ((charCode > 47 && charCode < 58) || (charCode > 64 && charCode < 91) || (charCode > 96 && charCode < 123) || charCode == 8 || charCode == 9 || charCode == 45 || (ctrl && charCode == 86) || ctrl && charCode == 67) {
return true;
} else {
$(":text").live("cut copy paste", function (e) {
e.preventDefault();
});
return false;
}
}
But it doesnt block special characters when pasting, only in entering,
suppose that you have a Input
<input id="textInput" name="textInput">
and you have the following script to validate the copy:
$(function(){
$( "#textInput" ).bind( 'paste',function()
{
setTimeout(function()
{
//get the value of the input text
var data= $( '#textInput' ).val() ;
//replace the special characters to ''
var dataFull = data.replace(/[^\w\s]/gi, '');
//set the new value of the input text without special characters
$( '#textInput' ).val(dataFull);
});
});
});
You could use a 3rd party plugin like jquery.alphanum, it works for paste (ctrl+v) too.
The code looks like this :
$("input").alphanum();
Or you could use it in a more spceficied way like this :
$("#elemet").alphanum({
allow : "asd",
disallow : "!##",
allowUpper : false
});
The above code you need to add it into your JQuery declaration.
I mention the fact that you can also modify the blacklist array from the script jquery.alphanum.js on line 124. You will find a function name getBlacklistAscii, in that you modify var blacklist = ... to what suits you.
Not an answer, just a comment regarding:
var ctrl;
ctrl = (document.all) ? event.ctrlKey:evt.modifiers & Event.CONTROL_MASK;
Please learn to use feature detection, inferring behaviour based on object inference is doomed to fail at least some of the time.
Also, don't use the key code, test the actual characters. E.g if you just want to allow letters, numbers and few others:
function hasInvalidChars(s) {
// allow letters, spaces, numbers only
var validChars = /[\w\s\d]/gi;
var x = s.replace(validChars, '');
return !!x.length;
}
alert(hasInvalidChars('asdf1234 1234asd')); // false
alert(hasInvalidChars('asdf1.234 1234asd')); // true
Expand the set of valid characters to whatever you want.
Oh, if you want it as a one–liner:
function hasInvalidChars(s) {
return !!s.replace(/[\w\s\d]/gi, '').length;
}
I have changed a bit the script provided by Christian.
This version replaces everything that is not between spaces (ASCII DEC 32) to tilde (ASCII DEC 126) and whitespace characters. Meaning all characters that are not-visible should be removed.
If you add the class api_clean_characters in a Jquery environment this should work out of the box.
<textarea class="api_clean_characters"></textarea>
$(function(){
$( ".api_clean_characters" ).bind( 'paste',function(ev)
{
var $target = $(ev.target);
setTimeout(function()
{
//get the value of the input text
var data= $target.val() ;
//replace the special characters to ''
var dataFull = data.replace(/[^ -~\s]/gi, '');
//set the new value of the input text without special characters
$target.val(dataFull);
});
});
});
How to do that?
I tried:
var key = event.which || event.keyCode || event.charCode;
if(key == 8) alert('backspace');
but it doesn't work...
If I do the same on the keypress event it works, but I don't want to use keypress because it outputs the typed character in my input field. I need to be able to control that
my code:
$('#content').bind('input', function(event){
var text = $(this).val(),
key = event.which || event.keyCode || event.charCode;
if(key == 8){
// here I want to ignore backspace and del
}
// here I'm doing my stuff
var new_text = 'bla bla'+text;
$(this).val(new_text);
});
no character should be appended in my input, besides what I'm adding with val()
actually the input from the user should be completely ignored, only the key pressing action is important to me
Use .onkeydown and cancel the removing with return false;. Like this:
var input = document.getElementById('myInput');
input.onkeydown = function() {
var key = event.keyCode || event.charCode;
if( key == 8 || key == 46 )
return false;
};
Or with jQuery, because you added a jQuery tag to your question:
jQuery(function($) {
var input = $('#myInput');
input.on('keydown', function() {
var key = event.keyCode || event.charCode;
if( key == 8 || key == 46 )
return false;
});
});
event.key === "Backspace"
More recent and much cleaner: use event.key. No more arbitrary number codes!
input.addEventListener('keydown', function(event) {
const key = event.key; // const {key} = event; ES6+
if (key === "Backspace" || key === "Delete") {
return false;
}
});
Mozilla Docs
Supported Browsers
With jQuery
The event.which property normalizes event.keyCode and event.charCode. It is recommended to watch event.which for keyboard key input.
http://api.jquery.com/event.which/
jQuery('#input').on('keydown', function(e) {
if( e.which == 8 || e.which == 46 ) return false;
});
It's an old question, but if you wanted to catch a backspace event on input, and not keydown, keypress, or keyup—as I've noticed any one of these break certain functions I've written and cause awkward delays with automated text formatting—you can catch a backspace using inputType:
document.getElementsByTagName('input')[0].addEventListener('input', function(e) {
if (e.inputType == "deleteContentBackward") {
// your code here
}
});
keydown with event.key === "Backspace" or "Delete"
More recent and much cleaner: use event.key. No more arbitrary number codes!
input.addEventListener('keydown', function(event) {
const key = event.key; // const {key} = event; ES6+
if (key === "Backspace" || key === "Delete") {
return false;
}
});
Modern style:
input.addEventListener('keydown', ({key}) => {
if (["Backspace", "Delete"].includes(key)) {
return false
}
})
Mozilla Docs
Supported Browsers
Have you tried using 'onkeydown'?
This is the event you are looking for.
It operates before the input is inserted and allows you to cancel char input.
$('div[contenteditable]').keydown(function(e) {
// trap the return key being pressed
if (e.keyCode === 13 || e.keyCode === 8)
{
return false;
}
});
InputEvent.inputType can be used for Backspace detection Mozilla Docs.
It works on Chrome desktop, Chrome Android and Safari iOS.
<input type="text" id="test" />
<script>
document.getElementById("test").addEventListener('input', (event) => {
console.log(event.inputType);
// Typing of any character event.inputType = 'insertText'
// Backspace button event.inputType = 'deleteContentBackward'
// Delete button event.inputType = 'deleteContentForward'
})
</script>
on android devices using chrome we can't detect a backspace.
You can use workaround for it:
var oldInput = '',
newInput = '';
$("#ID").keyup(function () {
newInput = $('#ID').val();
if(newInput.length < oldInput.length){
//backspace pressed
}
oldInput = newInput;
})
//Here's one example, not sure what your application is but here is a relevant and likely application
function addDashesOnKeyUp()
{
var tb = document.getElementById("tb1");
var key = event.which || event.keyCode || event.charCode;
if((tb.value.length ==3 || tb.value.length ==7 )&& (key !=8) )
{
tb.value += "-"
}
}
Live demo
Javascript
<br>
<input id="input">
<br>
or
<br>
jquery
<br>
<input id="inpu">
<script type="text/javascript">
var myinput = document.getElementById('input');
input.onkeydown = function() {
if (event.keyCode == 8) {
alert('you pressed backspace');
//event.preventDefault(); remove // to prevent backspace
}
if (event.keyCode == 46) {
alert('you pressed delete');
//event.preventDefault(); remove // to prevent delete
}
};
//jquery code
$('#inpu').on('keydown', function(e) {
if (event.which == 8) {
alert('you pressed backspace');
//event.preventDefault(); remove // to prevent backspace
}
if (event.which == 46) {
alert('you pressed delete');
//event.preventDefault(); remove // to prevent delete
}
});
</script>
I'm using the following Javascript to restrict a text field on my website to only accept numerical input, and no other letters or characters. The problem is, it REALLY rejects all other key inputs, like ctrl-A to select the text, or even any other browser functions like ctrl-T or ctrl-W while the text box is selected. Does anyone know of a better script to only allow numerical input, but not block normal commands (that aren't being directly input into the field)? Thanks
Here is the code I'm using now:
function numbersonly(e, decimal)
{
var key;
var keychar;
if (window.event)
key = window.event.keyCode;
else if (e)
key = e.which;
else
return true;
keychar = String.fromCharCode(key);
if ((key==null) || (key==0) || (key==8) || (key==9) || (key==13) || (key==27))
return true;
else if ((("0123456789").indexOf(keychar) > -1))
return true;
else if (decimal && (keychar == "."))
return true;
else
return false;
}
Edit: None of the solutions provided have solved my problem of allowing commands like ctrl-A while the text box is selected. That was the whole point of my asking here, so I have gone back to using my original script. Oh well.
This is something I made another time for just numbers, it will allow all the formatters as well.
jQuery
$('input').keypress(function(e) {
var a = [];
var k = e.which;
for (i = 48; i < 58; i++)
a.push(i);
if (!(a.indexOf(k)>=0))
e.preventDefault();
});
Try it
http://jsfiddle.net/zpg8k/
As a note, you'll want to filter on submit/server side as well, for sake of pasting/context menu and browsers that don't support the paste event.
Edit to elaborate on multiple methods
I see you're bouncing around the 'accepted' answer, so I'll clear something up. You can really use any of the methods listed here, they all work. What I'd personally do is use mine for live client side filtering, and then on submit and server side use RegEx as suggested by others. However, no client side by itself will be 100% effective as there is nothing stopping me from putting document.getElementById('theInput').value = 'Hey, letters.';
in the console and bypassing any clientside verification (except for polling, but I could just cancel the setInterval from the console as well). Use whichever client side solution you like, but be sure you implement something on submit and server side as well.
Edit 2 - #Tim Down
Alright, per the comments I had to adjust two things I didn't think of. First, keypress instead of keydown, which has been updated, but the lack of indexOf in IE (seriously Microsoft!?) breaks the example above as well. Here's an alternative
$('input').keypress(function(e) {
var a = [];
var k = e.which;
for (i = 48; i < 58; i++)
a.push(i);
if (!($.inArray(k,a)>=0))
e.preventDefault();
});
New jsfiddle: http://jsfiddle.net/umNuB/
This works in IE, Chrome AND Firefox:
<input type="text" onkeypress="return event.charCode === 0 || /\d/.test(String.fromCharCode(event.charCode));" />
.keypress(function(e)
{
var key_codes = [48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 0, 8];
if (!($.inArray(e.which, key_codes) >= 0)) {
e.preventDefault();
}
});
You need Backspace and Delete keys too ;)
http://jsfiddle.net/PgHFp/
<html>
<head>
<title>Test</title>
<script language="javascript">
function checkInput(ob) {
var invalidChars = /[^0-9]/gi
if(invalidChars.test(ob.value)) {
ob.value = ob.value.replace(invalidChars,"");
}
}
</script>
</head>
<body>
<input type="text" onkeyup="checkInput(this)"/>
</body>
</html>
Just use regex to get rid of any non number characters whenever a key is pressed or the textbox loses focus.
var numInput;
window.onload = function () {
numInput = document.getElementById('numonly');
numInput.onkeydown = numInput.onblur = numInput.onkeyup = function()
{
numInput.value = numInput.value.replace(/[^0-9]+/,"");
}
}
The only event that contains information about the character typed is keypress. Anything character-related you may infer from the keyCode property of keydown or keyup events is unreliable and dependent on a particular keyboard mapping. The following will prevent non-numeric keyboard input all major browsers by using the character obtained from the keypress event. It won't prevent the user from pasting or dragging non-numeric text in.
var input = document.getElementById("your_input");
input.onkeypress = function(evt) {
evt = evt || window.event;
if (!evt.ctrlKey && !evt.metaKey && !evt.altKey) {
var charCode = (typeof evt.which == "undefined") ? evt.keyCode : evt.which;
if (charCode && !/\d/.test(String.fromCharCode(charCode))) {
return false;
}
}
};
I use this:
oEl.keypress(function(ev)
{
var sKey = String.fromCharCode(ev.which);
if (!sKey.match(/[0-9]/) || !sKey === "")
ev.preventDefault();
});
The advantage is, that every key which does not provide an input to the field is still allowed, so you don't have to worry about every single special key. Even combos like CTRL + R do still work.
EDIT
As this is not working in Firefox I had to modify the function a little:
oEl.keypress(function(ev)
{
var iKeyCode = ev.which || ev.keyCode;
var aSpecialKeysForFirefox = [8, 9, 13, 27, 37, 38, 39, 40, 46];
var sKey = String.fromCharCode(iKeyCode);
if (sKey !== "" && $.inArray(iKeyCode, aSpecialKeysForFirefox ) < 0 && !sKey.match(/[0-9]/)) {
ev.preventDefault();
}
});
Explanation
All Browsers handle jquerys keypress event differently. To make it work in FF the $.inArray check is added. As firefoxs keypress-event doesn't trigger when combinations like strg+tab are used, but the others do, the key.match approach still adds a little value to the latter, as it enables those combinations.
Maybe you are using bootstrap. If so, this may suffice:
<input type="text" data-mask="9999999">
Input mask
The following code is something I use extensively. I found the script in a forum, but modified and expanded it to accommodate my needs:
<script type="text/javascript">
// Restrict user input in a text field
// create as many regular expressions here as you need:
var digitsOnly = /[1234567890]/g;
var integerOnly = /[0-9\.]/g;
var alphaOnly = /[A-Za-z]/g;
var usernameOnly = /[0-9A-Za-z\._-]/g;
function restrictInput(myfield, e, restrictionType, checkdot){
if (!e) var e = window.event
if (e.keyCode) code = e.keyCode;
else if (e.which) code = e.which;
var character = String.fromCharCode(code);
// if user pressed esc... remove focus from field...
if (code==27) { this.blur(); return false; }
// ignore if the user presses other keys
// strange because code: 39 is the down key AND ' key...
// and DEL also equals .
if (!e.ctrlKey && code!=9 && code!=8 && code!=36 && code!=37 && code!=38 && (code!=39 || (code==39 && character=="'")) && code!=40) {
if (character.match(restrictionType)) {
if(checkdot == "checkdot"){
return !isNaN(myfield.value.toString() + character);
} else {
return true;
}
} else {
return false;
}
}
}
</script>
Different usage methods would be:
<!-- To accept only alphabets -->
<input type="text" onkeypress="return restrictInput(this, event, alphaOnly);">
<!-- To accept only numbers without dot -->
<input type="text" onkeypress="return restrictInput(this, event, digitsOnly);">
<!-- To accept only numbers and dot -->
<input type="text" onkeypress="return restrictInput(this, event, integerOnly);">
<!-- To accept only numbers and only one dot -->
<input type="text" onkeypress="return restrictInput(this, event, integerOnly, 'checkdot');">
<!-- To accept only characters for a username field -->
<input type="text" onkeypress="return restrictInput(this, event, usernameOnly);">
Add <script type="text/javascript" src="jquery.numeric.js"></script> then use
$("element").numeric({ decimal: false, negative: false });
shorter way and easy to understand:
$('#someID').keypress(function(e) {
var k = e.which;
if (k <= 48 || k >= 58) {e.preventDefault()};
});
This is a variation on Robert's answer that allows a single decimal point to be entered. If a decimal point has already been entered, only numbers are accepted as input.
JSFiddle - decimal number input
// Allow only decimal number input
$('#decimalInput').keypress(function (e) {
var a = [];
var k = e.which;
for (i = 48; i < 58; i++)
a.push(i);
// allow a max of 1 decimal point to be entered
if (this.value.indexOf(".") === -1) {
a.push(46);
}
if (!(a.indexOf(k) >= 0)) e.preventDefault();
$('span').text('KeyCode: ' + k);
});
I know that there are already many answers but for the sake of simplicity i would like to add another answer which is simple and self explanatory in which we do not have to remember keycodes and it also works across all browsers.
document.getElementById('myinput').onkeydown = function(e)
{
console.log(e.key);
//console.log(e.target.value);
switch (e.key)
{
case "1":
case "2":
case "3":
case "4":
case "5":
case "6":
case "7":
case "8":
case "9":
case "0":
case "Backspace":
return true;
break;
case ".":
if (e.target.value.indexOf(".") == -1)
{
return true;
}
else
{
return false;
}
break;
default:
return false;
}
}
<input type="text" placeholder="Enter Value" id="myinput" />
It's worth pointing out that no matter how tightly you manage to control this via the front end (Javascript, HTML, etc), you still need to validate it at the server, because there's nothing to stop a user from turning off javascript, or even deliberately posting junk to your form to try to hack you.
My advice: Use the HTML5 markup so that browsers which support it will use it. Also use the JQuery option previously suggested (the inital solution may have flaws, but it seems like the comments have been working through that). And then do server-side validation as well.
this will enable the numpad inputs also.
.keydown(function(event){
if(event.keyCode == 8 || event.keyCode == 46)
return true;
if(event.keyCode >= 96 && event.keyCode <= 105)
return true;
if(isNaN(parseInt(String.fromCharCode(event.keyCode),10)))
return false;
});
In order to block anything but numbers from being input into a text field but still allowing for other buttons to work (such as delete, shift, tab, etc.) look at a reference of the Javascript key codes; anything from 65 on up (to 222) can be blocked.
Using Jquery and Javascript, that would look like:
$('#textFieldId').keydown(function(event) {
if ( event.keyCode > 64 ) {
event.preventDefault();
}
});
The key codes will be the same in Javascript whether or not Jquery is used.
Here is my solution: a combination of the working ones below.
var checkInput = function(e) {
if (!e) {
e = window.event;
}
var code = e.keyCode || e.which;
if (!e.ctrlKey) {
//46, 8, 9, 27, 13 = backspace, delete, tab, escape, and enter
if (code == 8 || code == 13 || code == 9 || code == 27 || code == 46)
return true;
//35..39 - home, end, left, right
if (code >= 35 && code <= 39)
return true;
//numpad numbers
if (code >= 96 && code <= 105)
return true;
//keyboard numbers
if (isNaN(parseInt(String.fromCharCode(code), 10))) {
e.preventDefault();
return false;
}
}
return true;
};
I came across your question while trying to figure this out myself. Here is the solution that I came up with.
// Prevent user from entering non-numeric characters in number boxes.
(function (inputs) {
var input;
var f = function (e) {
var unicodeRe = /U\+(\d+)/;
// Chrome doesn't support the standard key property, so use keyIdentifier instead.
// Instead of the actual character that "key" returns, keyIdentifier returns
// A string such as "U+004F" representing the unicode character.
// For special characters (e.g., "Shift", a string containing the name of the key is returned.)
var ch = e.key || e.keyIdentifier;
var match = ch.match(unicodeRe);
// keyIdentifier returns a unicode. Convert to string.
if (match) {
ch = String.fromCharCode(Number.parseInt(match[1], 16));
}
console.log(ch);
if (ch.length === 1 && /[^0-9]/.test(ch)) {
if (!/[\b]/.test(ch)) { // Don't prevent backspace.
e.preventDefault();
}
}
};
for (var i = 0, l = inputs.length; i < l; i += 1) {
input = inputs[i];
input.onkeydown = f;
}
}(document.querySelectorAll("input[type=number],#routeFilterBox")));
Edit: I've discovered that my solution does not allow the user to enter numbers via the numpad in Chrome. The 0-9 keypad keys seem to be returning the character "`" for 0 and A-I for the rest of the number keys.
All of the answers are outdated, lengthy and will cause annoyance to your users. Most of them don’t even filter or allow pasted content.
Instead of filtering the input, do some validation before submitting the form and then also server-side.
HTML has validation included:
<input type="number" pattern="[0-9]+">
This also enables the number keyboard on mobile.
This is my plugin for that case:
(function( $ ) {
$.fn.numbers = function(options) {
$(this).keypress(function(evt){
var setting = $.extend( {
'digits' : 8
}, options);
if($(this).val().length > (setting.digits - 1) && evt.which != 8){
evt.preventDefault();
}
else{
if(evt.which < 48 || evt.which > 57){
if(evt.keyCode != 8){
evt.preventDefault();
}
}
}
});
};
})( jQuery );
Use:
$('#limin').numbers({digits:3});
$('#limax').numbers();
There is my current solution of numeric input, need to test in different browsers but seems to work
Support comma and period delimiter (czech native is comma), space and numpad/keyboard numbers input. Allow Ctrl+C Ctrl+A or Ctrl+X, arrow navigation and delete block Ctrl+V. React on escape key by blurring input.
Watch my Coffee script:
(($) ->
$.fn.onlyNumbers = ->
#each ->
$(#).keydown (e) ->
# get code of key
code = if e.keyCode then e.keyCode else e.which
return $(#).blur() if code is 27 # blur on escape
return if code in [46, 8, 9, 13] # 46, 8, 9, 27, 13 = backspace, delete, tab, escape, and enter
return if (e.ctrlKey or e.metaKey) and code in [65, 67, 88] # ctrl|command + [a, c, x]
return if code in [96..105] # numpad numbers
return if code in [48..57] # numbers on keyboard
return if code in [35..39] # 35..39 - home, end, left, right
return if code in [188, 190, 32] # comma, period, space
return if code in [44] # comma, period,
e.returnValue = false # IE hate you
e.preventDefault();
$(#).keypress (e) ->
code = if e.keyCode then e.keyCode else e.which
return if code in [44, 46, 32] # comma, period, space
return if code in [48..57] # numbers on keyboard
e.returnValue = false # IE hate you
e.preventDefault();
) jQuery
You can get compiled Javascript here http://goo.gl/SbyhXN
My functions:
$('.input_integer_only').on('input', function(e) {
$(this).val($(this).val().replace(/[^0-9]/g, ''));
});
$('.input_float_only').on('input', function(e) {
var $var = $(this).val().replace(/[^0-9\.]/g, '');
var $aVar = $var.split('.');
if($aVar.length > 2) {
$var = $aVar[0] + '.' + $aVar[1];
}
$(this).val($var);
});
You can make changes to accept the keycode for Ctrl keys: 17, 18, 19, 20.
Then your code will be like:
function numbersonly(e, decimal) {
var key;
var keychar;
if (window.event)
key = window.event.keyCode;
else if (e)
key = e.which;
else
return true;
keychar = String.fromCharCode(key);
if ((key==null) || (key==0) || (key==8) || (key==9) || (key==13) || (key==27) || (key==17) || (key==18) || (key==19) || (key==20))
return true;
else if ((("0123456789").indexOf(keychar) > -1))
return true;
else if (decimal && (keychar == "."))
return true;
else
return false;
}
document.getElementById('myinput').onkeydown = function(e) {
if(!((e.keyCode > 95 && e.keyCode < 106)
|| (e.keyCode > 47 && e.keyCode < 58)
|| e.keyCode == 8
|| e.keyCode == 9)) {
return false;
}
}
You can do like this to accept only Numbers in text Box,
function onChange(event){
var ckeckChars = /[^0-9]/gi;
if(checkChars.test(event.target.value)) {
event.target.value = event.target.value.replace(ckeckChars,"");
}
I am using below in Angular to restrict character
in HTML
For Number Only
<input
type="text"
id="score"
(keypress) ="onInputChange($event,'[0-9]')"
maxlength="3"
class="form-control">
for Alphabets Only
<input
type="text"
id="state"
(keypress) ="onInputChange($event,'[a-zA-Z]')"
maxlength="3"
class="form-control">
In TypeScript
onInputChange(event: any, inpPattern:string): void {
var input = event.key;
if(input.match(inpPattern)==null){
event.preventDefault();
}
}
This JavaScript function will be used to restrict alphabets and
special characters in Textbox , only numbers, delete, arrow keys and
backspace will be allowed. JavaScript Code Snippet - Allow Numbers
in TextBox, Restrict Alphabets and Special Characters
Tested in IE & Chrome.
JavaScript function
<script type="text/javascript">
/*code: 48-57 Numbers
8 - Backspace,
35 - home key, 36 - End key
37-40: Arrow keys, 46 - Delete key*/
function restrictAlphabets(e){
var flag = false;
var x = e.which || e.keycode;
if ((x >= 48 && x <= 57) || x == 8 ||
(x >= 35 && x <= 40) || x == 46)
flag = true;
else
flag = false;
if (flag && e.keyCode === 46 && $(e.currentTarget).val().split('.').length === 2) {
flag = false;
}
return flag;
}
</script>
HTML Source Code with JavaScript
<html>
<head>
<title>JavaScript - Allow only numbers in TextBox (Restrict Alphabets and Special Characters).</title>
<script type="text/javascript">
/*code: 48-57 Numbers
8 - Backspace,
35 - home key, 36 - End key
37-40: Arrow keys, 46 - Delete key*/
function restrictAlphabets(e){
var x=e.which||e.keycode;
if((x>=48 && x<=57) || x==8 ||
(x>=35 && x<=40)|| x==46)
return true;
else
return false;
}
</script>
</head>
<body style="text-align: center;">
<h1>JavaScript - Allow only numbers in TextBox (Restrict Alphabets and Special Characters).</h1>
<big>Enter numbers only: </big>
<input type="text" onkeypress='return restrictAlphabets(event)'/>
</body>
</html>
Refrence
You can handle te event on html by introducing keypresshandler function
function keypresshandler(event)
{
var charCode = event.keyCode;
//You condition
if (charCode == 58 ){
event.preventDefault();
return false;
}
}
Javascript is often used on the browser client side to perform simple tasks that would otherwise require a full postback to the server. Many of those simple tasks involve processing text or characters entered into a form element on a web page, and it is often necessary to know the javascript keycode associated with a character. Here is a reference.
Press a key in the text box below to see the corresponding Javascript key code.
function restrictCharacters(evt) {
evt = (evt) ? evt : window.event;
var charCode = (evt.which) ? evt.which : evt.keyCode;
if (((charCode >= '48') && (charCode <= '57')) || (charCode == '44')) {
return true;
}
else {
return false;
}
}
Enter Text:
<input type="text" id="number" onkeypress="return restrictCharacters(event);" />