How to know if .keyup() is a character key (jQuery)
$("input").keyup(function() {
if (key is a character) { //such as a b A b c 5 3 2 $ # ^ ! ^ * # ...etc not enter key or shift or Esc or space ...etc
/* Do stuff */
}
});
You can't do this reliably with the keyup event. If you want to know something about the character that was typed, you have to use the keypress event instead.
The following example will work all the time in most browsers but there are some edge cases that you should be aware of. For what is in my view the definitive guide on this, see http://unixpapa.com/js/key.html.
$("input").keypress(function(e) {
if (e.which !== 0) {
alert("Charcter was typed. It was: " + String.fromCharCode(e.which));
}
});
keyup and keydown give you information about the physical key that was pressed. On standard US/UK keyboards in their standard layouts, it looks like there is a correlation between the keyCode property of these events and the character they represent. However, this is not reliable: different keyboard layouts will have different mappings.
Note: In hindsight this was a quick and dirty answer, and may not work in all situations. To have a reliable solution, see Tim Down's answer (copy pasting that here as this answer is still getting views and upvotes):
You can't do this reliably with the keyup event. If you want to know
something about the character that was typed, you have to use the
keypress event instead.
The following example will work all the time in most browsers but
there are some edge cases that you should be aware of. For what is in
my view the definitive guide on this, see
http://unixpapa.com/js/key.html.
$("input").keypress(function(e) {
if (e.which !== 0) {
alert("Character was typed. It was: " + String.fromCharCode(e.which));
}
});
keyup and keydown give you information about the physical key that
was pressed. On standard US/UK keyboards in their standard layouts, it
looks like there is a correlation between the keyCode property of
these events and the character they represent. However, this is not
reliable: different keyboard layouts will have different mappings.
The following was the original answer, but is not correct and may not work reliably in all situations.
To match the keycode with a word character (eg., a would match. space would not)
$("input").keyup(function(event)
{
var c= String.fromCharCode(event.keyCode);
var isWordcharacter = c.match(/\w/);
});
Ok, that was a quick answer. The approach is the same, but beware of keycode issues, see this article in quirksmode.
I'm not totally satisfied with the other answers given. They've all got some kind of flaw to them.
Using keyPress with event.which is unreliable because you can't catch a backspace or a delete (as mentioned by Tarl).
Using keyDown (as in Niva's and Tarl's answers) is a bit better, but the solution is flawed because it attempts to use event.keyCode with String.fromCharCode() (keyCode and charCode are not the same!).
However, what we DO have with the keydown or keyup event is the actual key that was pressed (event.key).
As far as I can tell, any key with a length of 1 is a character (number or letter) regardless of which language keyboard you're using. Please correct me if that's not true!
Then there's that very long answer from asdf. That might work perfectly, but it seems like overkill.
So here's a simple solution that will catch all characters, backspace, and delete. (Note: either keyup or keydown will work here, but keypress will not)
$("input").keydown(function(event) {
var isWordCharacter = event.key.length === 1;
var isBackspaceOrDelete = event.keyCode === 8 || event.keyCode === 46;
if (isWordCharacter || isBackspaceOrDelete) {
// do something
}
});
This helped for me:
$("#input").keyup(function(event) {
//use keyup instead keypress because:
//- keypress will not work on backspace and delete
//- keypress is called before the character is added to the textfield (at least in google chrome)
var searchText = $.trim($("#input").val());
var c= String.fromCharCode(event.keyCode);
var isWordCharacter = c.match(/\w/);
var isBackspaceOrDelete = (event.keyCode == 8 || event.keyCode == 46);
// trigger only on word characters, backspace or delete and an entry size of at least 3 characters
if((isWordCharacter || isBackspaceOrDelete) && searchText.length > 2)
{ ...
If you only need to exclude out enter, escape and spacebar keys, you can do the following:
$("#text1").keyup(function(event) {
if (event.keyCode != '13' && event.keyCode != '27' && event.keyCode != '32') {
alert('test');
}
});
See it actions here.
You can refer to the complete list of keycode here for your further modification.
I wanted to do exactly this, and I thought of a solution involving both the keyup and the keypress events.
(I haven't tested it in all browsers, but I used the information compiled at http://unixpapa.com/js/key.html)
Edit: rewrote it as a jQuery plugin.
(function($) {
$.fn.normalkeypress = function(onNormal, onSpecial) {
this.bind('keydown keypress keyup', (function() {
var keyDown = {}, // keep track of which buttons have been pressed
lastKeyDown;
return function(event) {
if (event.type == 'keydown') {
keyDown[lastKeyDown = event.keyCode] = false;
return;
}
if (event.type == 'keypress') {
keyDown[lastKeyDown] = event; // this keydown also triggered a keypress
return;
}
// 'keyup' event
var keyPress = keyDown[event.keyCode];
if ( keyPress &&
( ( ( keyPress.which >= 32 // not a control character
//|| keyPress.which == 8 || // \b
//|| keyPress.which == 9 || // \t
//|| keyPress.which == 10 || // \n
//|| keyPress.which == 13 // \r
) &&
!( keyPress.which >= 63232 && keyPress.which <= 63247 ) && // not special character in WebKit < 525
!( keyPress.which == 63273 ) && //
!( keyPress.which >= 63275 && keyPress.which <= 63277 ) && //
!( keyPress.which === event.keyCode && // not End / Home / Insert / Delete (i.e. in Opera < 10.50)
( keyPress.which == 35 || // End
keyPress.which == 36 || // Home
keyPress.which == 45 || // Insert
keyPress.which == 46 || // Delete
keyPress.which == 144 // Num Lock
)
)
) ||
keyPress.which === undefined // normal character in IE < 9.0
) &&
keyPress.charCode !== 0 // not special character in Konqueror 4.3
) {
// Normal character
if (onNormal) onNormal.call(this, keyPress, event);
} else {
// Special character
if (onSpecial) onSpecial.call(this, event);
}
delete keyDown[event.keyCode];
};
})());
};
})(jQuery);
I never liked the key code validation. My approach was to see if the input have text (any character), confirming that the user is entering text and no other characters
$('#input').on('keyup', function() {
var words = $(this).val();
// if input is empty, remove the word count data and return
if(!words.length) {
$(this).removeData('wcount');
return true;
}
// if word count data equals the count of the input, return
if(typeof $(this).data('wcount') !== "undefined" && ($(this).data('wcount') == words.length)){
return true;
}
// update or initialize the word count data
$(this).data('wcount', words.length);
console.log('user tiped ' + words);
// do you stuff...
});
<html lang="en">
<head>
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
</head>
<body>
<input type="text" name="input" id="input">
</body>
</html>
Related
I have been using jquery to capture the keydown event and validate the entered text for different cases like: characters only, alpha-numeric, characters and spaces etc.
Regex used:
Characters with spaces: ^[a-zA-Z ]+$
Characters only: ^[a-zA-Z]+$
Alphanumerics: ^[a-zA-Z0-9]+$
This is how I am using the bind function:
$('.chars_and_space_only').bind('keydown', function (event) {
// http://stackoverflow.com/a/8833854/260665
var eventCode = !event.charCode ? event.which : event.charCode;
if((eventCode >= 37 && eventCode <= 40) || eventCode == 8 || eventCode == 9 || eventCode == 46) { // Left / Right Arrow, Backspace, Delete keys
return;
}
// http://stackoverflow.com/a/8833854/260665
var regex = new RegExp("^[a-zA-Z ]+$");
var key = String.fromCharCode(eventCode);
if (!regex.test(key)) {
event.preventDefault();
return false;
}
});
All of above uses cases are working fine, however I have to now include characters, spaces, apostrophe and periods. So this is the method I have modified:
$(".chars_space_dots_apostrophes_only").bind('keydown', function (event) {
// http://stackoverflow.com/a/8833854/260665
var eventCode = !event.charCode ? event.which : event.charCode;
if((eventCode >= 37 && eventCode <= 40) || eventCode == 8 || eventCode == 9 || eventCode == 46) { // Left / Right Arrow, Backspace, Delete keys
return;
}
// http://stackoverflow.com/a/8833854/260665
var regex = new RegExp("^[a-zA-Z '.]+$");
var key = String.fromCharCode(eventCode);
if (!regex.test(key)) {
event.preventDefault();
return false;
}
});
This, strangely doesn't seem to work. Here is the fiddle: https://jsfiddle.net/ugu8f4y3/
Regex used: ^[a-zA-Z '.]+$
Regex validator does validate this text for the above regex:
Hello. World's
But the text field in fiddle does not allow me to enter periods and apostrophes, is there something I am missing here?
The problem is with jquery and the keydown event. Replace it with keypress and you'll be good to go. You should also only need to check in which.
keydown and keyup are important for cases when you're concerned with the position of the key's physical location. In this case you want to know that the key was depressed and handle the resulting input. jquery will normalize the character codes differently.
Further information about the differences between keypress, keydown and key up.
Updated Fiddle
I've an input box that I only want to allow letters, hyphen, space and backspace. All is good on chrome but on Firefox backspace (or charcode 8) does not work. - https://jsfiddle.net/npo7y7fr/
$(document).ready(function () {
$('.textInput').keypress(function (key) {
if ((key.charCode < 97 || key.charCode > 122) && (key.charCode < 65 || key.charCode > 90) && (key.charCode != 45)) return false;
});
});
I've tried adding && (key.charCode != 8) also changes keypress to others like 'keydown, keyup' etc...
Can anybody get this working in Firefox (40.0.3) or something that I can use instead?
Since Space will send keycode 32 and backspace will send 0 in Mozilla so that's why it is not working in mozilla.
change your script as below
$(document).ready(function () {
$('.textInput').keypress(function (key) {
if ((key.charCode < 97 || key.charCode > 122) && (key.charCode < 65 || key.charCode > 90) && (key.charCode != 45) && (key.charCode != 32) && (key.charCode != 0) ) return false;
});
});
hope this helps..!!
Instead of hardcoding some special keys, just skip the filtering for all of them. With the accepted solution, you still cancel arrow keys, Home, End, etc., which is a bad thing for the user.
As all special keys have a key field longer than 1 character, you can safely do this:
$(document).ready(function () {
$('.textInput').keypress(function (event) {
return event.key.length > 1 || event.ctrlKey || !!event.key.match(/[a-zA-Z \-]/);
});
});
The pressed key is accepted if it's a special key, it's been pressed simultaneously with the Ctrl key (to allow copying and pasting) or if it matches the regular expression (letters, space and hyphen).
As the user can paste invalid content, you should still remove illegal characters with the oninput event (probably something like ctrl.value.replace(/[^a-zA-Z \-]+/g, '')).
Rather than trying to control what the browser can enter into the input, it might be easier to just filter the contents of the textbox on keyup.
Consider the following:
$('.textInput').keyup(function() {
$(this).val( $(this).val().replace(/[^a-zA-Z]/,''));
});
Hope this helps.
I have a keypress function bound to an element, this element needs to only allow positive and negative decimal characters. i.e. 0-9, '.' , '-'
any other characters I need to prevent the character being inputted
Is there any way to achieve this in the current keypress function
$('.test').keyup(function (event) {
//if character is NOT ok i.e. 0-9, '.' , '-'
//STOP
..ELSE
//continue to do something
});
P.s. I am using jquery
One other way is to replace all illegal characters when typing:
$("selector").keyup(function (e) {
this.value = this.value.replace(/[^0-9\.-]/g, '');
});
May be useful, when user not typing text, but pasting it.
The key is inserted on keydown, so you should use that event instead. Then this should work:
$('.test').on('keyup', function(e){
e.preventDefault();
if(e.keyCode >= 48 && e.keyCode <= 57 // regular numbers
|| e.keyCode >= 96 && e.keyCode <= 106 // Numpad
|| e.keyCode === 189 // Minus
){
try{
parseInt($(this).val());
// Continue, this is a valid numeric value.
}catch(ex){
// Stop
}
}else {
// Stop
}
});
Hope this helps:
var string = '-10.56',
illegal = /[^0-9.-]/.test(string); // return true if illegal character found
I'm trying to build a communal wall, that appears the same for all those who access the web page, and syncs between users. I'm struggling to capture keyboard input correctly to apply to the canvas. My function is based on document.onkeydown, and can be seen in the 'script.js' referenced in the said web page. It can be seen working when you double click a word and the write.
Unfortunately this seems to be failing to capture anything but capital letters, and I'm looking for an alternate way to go about this. I've looked into the 'textInput' event, described in this page, however it seems to be only supported by WebKit browsers, and I want to build something which works generically. Can someone suggest an alternate way to go about capturing keyboard input for use in canvas? Or perhaps I'm doing something silly?
Code described is here:
document.onkeydown = keyHandler;
function keyHandler(e)
{
var pressedKey;
if (document.all) { e = window.event;
pressedKey = e.keyCode; }
if (e.which) {
pressedKey = e.which;
}
if (pressedKey == 8) {
e.cancelBubble = true; // cancel goto history[-1] in chrome
e.returnValue = false;
}
if (pressedKey == 27)
{
// escape key was pressed
keyCaptureEdit = null;
}
if (pressedKey != null && keyCaptureEdit != null)
{
keyCaptureEdit.callback(pressedKey);
}
}
... Later on in code describing each text object ...
keyCaptureEdit.callback = function (keyCode) {
var keyCaptured = String.fromCharCode(keyCode);
if (keyCaptured == "\b" ) { //backspace character
t.attrs.timestamp = t.attrs.timestamp + 1;
t.setText(t.getText().slice(0, -1));
}
else if (keyCode == 32 || keyCode >= 48 && keyCode <= 57 || keyCode >= 65 && keyCode <= 90)
{
t.attrs.timestamp = t.attrs.timestamp + 1;
t.setText(t.getText() + keyCaptured);
}
layer.draw();
}
Well one trivial way to change your code would be to keep track of the shift key:
...
{
keyCaptureEdit.callback(pressedKey, e.shiftKey); // <-- keep track of shift key
}
}
...
keyCaptureEdit.callback = function (keyCode, shift) {
var keyCaptured = String.fromCharCode(keyCode);
// shift key not pressed? Then it's lowercase
if (shift === false) keyCaptured = keyCaptured.toLowerCase()
But that doesn't account for CapsLock.
In jQuery its really simple because the right key code is done for you:
$(document).keypress(function(event) {
var keyCaptured = String.fromCharCode(event.keyCode);
console.log(keyCaptured);
});
In that example the console will correctly log P or p depending on what would be typed.
I am wondering how to create an event listener, so that when any of the character keys are pressed a form pops up and the first input is in focus and is receiving the input, sort of like the just type search style for the webOS 2.0 operating system, but for a contact form. Is there anyway to do so? In case your not familiar here is a link to the webos just type feature
http://www.youtube.com/watch?v=ixPsB7-tVGo
I don't know if you can only subscribe to letter keys.
Your best bet would be to use jQuery to subscribe to .keydown() / .keyup() and check the keycode of the event to see which letter it is. If it's not a letter, don't do anything.
Like this:
$('#target').keydown(function(event) {
if (event.keyCode >= 65 && event.keyCode <= 90) { // if a letter pressed
// play that funky music.
}
});
More on $.keydown.
List of key codes.
Use the keypress event for anything character related. keydown and keyup cannot be used reliably for this purpose. The following is adapted from my answer to a related recent question:
function isCharacterKeyPress(evt) {
if (typeof evt.which == "undefined") {
// This is IE, which only fires keypress events for printable keys
return true;
} else if (typeof evt.which == "number" && evt.which > 0) {
// In other browsers except old versions of WebKit, evt.which is
// only greater than zero if the keypress is a printable key.
// We need to filter out backspace and ctrl/alt/meta key combinations
return !evt.ctrlKey && !evt.metaKey && !evt.altKey && evt.which != 8;
}
return false;
}
var input = document.getElementById("your_input_id");
input.onkeypress = function(evt) {
evt = evt || window.event;
if (isCharacterKeyPress(evt)) {
// Do your stuff here
alert("Character!");
}
};