I have some code which is a basic highlighting system, when I try to catch backspaces, I can't catch them, even when I use onkeydown and keypress.
I am using jQuery to get the events and register the function calls. Here is my code:
if (e.charCode == 8 || e.charCode == 46 || e.charCode == 35) {
if (errCount) {
errCount--;
}
backLetter(index);
index--;
}
Use .which, as in e.which == 8
https://jsfiddle.net/skdreow5/1/
var xTriggered = 0;
$( "#target" ).keydown(function( event ) {
if ( event.which == 13 ) {
event.preventDefault();
}
if ( event.which == 8 ||
event.which == 46 ||
event.which == 35 ) {
console.log("backspaced: " + event.which);
}
xTriggered++;
var msg = "Handler for .keydown() called " + xTriggered + " time(s).";
console.log(msg);
});
DEMO
Regarding e.charCode
This feature is non-standard and is not on a standards track. Do not
use it on production sites facing the Web: it will not work for every
user. There may also be large incompatibilities between
implementations and the behavior may change in the future.
Either use e.which or e.keyCode to trap the backspace. Some browsers support e.which and some support e.keyCode. As part of jQuery concerned, they have normalized e.which in the event object. In case you're using jQuery go with e.which.
$(function() {
$("input").keyup(function(e) {
if(e.keyCode==8) {
alert("Backspace pressed");
}
});
});
Related
I want to apply a javascript background on my website. I found a ready one, but I recognize a problem on it. When you scrool with mouse on browser, zoom in or zoom out, it starts to look so strange. You can try it on your own from that demo link;
Demo
Also the html and css code of this animational background is in this link;
Link of HTML-CSS-Javascript of this demo
Can you help me, how can I prevent it from being zoomed in or zoomed out on a browser ?
You can only do it using jquery with below code,
$(document).keydown(function(event) {
if (event.ctrlKey==true && (event.which == '61' || event.which == '107' || event.which == '173' || event.which == '109' || event.which == '187' || event.which == '189' ) ) {
event.preventDefault();
}
// 107 Num Key +
// 109 Num Key -
// 173 Min Key hyphen/underscor Hey
// 61 Plus key +/= key
});
$(window).bind('mousewheel DOMMouseScroll', function (event) {
if (event.ctrlKey == true) {
event.preventDefault();
}
});
Note: Make sure you have included jquery in your code before this script.
My current code is like this
$('.textBoxClass').bind('keypress', function (e) {
return (e.which != 8 && e.which != 0 && (e.which < 48 || e.which > 57) && e.which != 46 && e.which != 43) ? false : true;
});
Use the jQuery keyup event.
You need to check if event.keyCode is + and if input field already contains +.
If yes, you can prevent the event with event.preventDefault().
Or you can use some third-part plugin like jqueryvalidation and use a regular expression.
Remember to validate the data serverside because javascript validation can be easily bypassed.
I am trying to capture ctrl+z key combination in javascript with this code:
<html>
<head>
<title>Untitled Document</title>
</head>
<body>
<script type='text/javascript'>
function KeyPress(e) {
var evtobj = window.event? event : e
//test1 if (evtobj.ctrlKey) alert("Ctrl");
//test2 if (evtobj.keyCode == 122) alert("z");
//test 1 & 2
if (evtobj.keyCode == 122 && evtobj.ctrlKey) alert("Ctrl+z");
}
document.onkeypress = KeyPress;
</script>
</body>
</html>
Commented line "test1" generates the alert if I hold down the ctrl key and press any other key.
Commented line "test2" generates the alert if I press the z key.
Put them together as per the line after "test 1 & 2", and holding down the ctrl key then pressing the z key does not generate the alert as expected.
What is wrong with the code?
Use onkeydown (or onkeyup), not onkeypress
Use keyCode 90, not 122
function KeyPress(e) {
var evtobj = window.event? event : e
if (evtobj.keyCode == 90 && evtobj.ctrlKey) alert("Ctrl+z");
}
document.onkeydown = KeyPress;
Online demo: http://jsfiddle.net/29sVC/
To clarify, keycodes are not the same as character codes.
Character codes are for text (they differ depending on the encoding, but in a lot of cases 0-127 remain ASCII codes). Key codes map to keys on a keyboard. For example, in unicode character 0x22909 means 好. There aren't many keyboards (if any) who actually have a key for this.
The OS takes care of transforming keystrokes to character codes using the input methods that the user configured. The results are sent to the keypress event. (Whereas keydown and keyup respond to the user pressing buttons, not typing text.)
For future folks who stumble upon this question, here’s a better method to get the job done:
document.addEventListener('keydown', function(event) {
if (event.ctrlKey && event.key === 'z') {
alert('Undo!');
}
});
Using event.key greatly simplifies the code, removing hardcoded constants. It has support for IE 9+.
Additionally, using document.addEventListener means you won’t clobber other listeners to the same event.
Finally, there is no reason to use window.event. It’s actively discouraged and can result in fragile code.
Ctrl+t is also possible...just use the keycode as 84 like
if (evtobj.ctrlKey && evtobj.keyCode == 84)
alert("Ctrl+t");
$(document).keydown(function(e){
if( e.which === 89 && e.ctrlKey ){
alert('control + y');
}
else if( e.which === 90 && e.ctrlKey ){
alert('control + z');
}
});
Demo
document.onkeydown = function (e) {
var special = e.ctrlKey || e.shiftKey;
var key = e.charCode || e.keyCode;
console.log(key.length);
if (special && key == 38 || special && key == 40 ) {
// enter key do nothing
e.preventDefault();
}
}
here is a way to block two keys, either shift+ or Ctrl+ key combinations.
&& helps with the key combinations, without the combinations, it blocks all ctrl or shift keys.
90 is the Z key and this will do the necessary capture...
function KeyPress(e){
// Ensure event is not null
e = e || window.event;
if ((e.which == 90 || e.keyCode == 90) && e.ctrlKey) {
// Ctrl + Z
// Do Something
}
}
Depending on your requirements you may wish to add a e.preventDefault(); within your if statement to exclusively perform your custom functionality.
The KeyboardEvent.keyCode is deprecated (link) think about using KeyboardEvent.key instead (link).
So, the solution would be something like this.
if (e.key === "z" && e.ctrlKey) {
alert('ctrl+z');
}
You can actually see it all in the KeyboardEvent when you use keydown event
Use this code for CTRL+Z. keycode for Z in keydown is 90 and the CTRL+Z is ctrlKey. check this keycode in your console area
$(document).on("keydown", function(e) {
console.log(e.keyCode, e.ctrlKey);
/*ctrl+z*/
if (e.keyCode === 90 && e.ctrlKey) { // this is confirmed with MacBook pro Monterey on 1, Aug 2022
{
//your code here
}
});
$(".tbSearchBox").keyup(function (event) {
if (event.keyCode == 13) {
alert("ye");
searchSet = $(this).val();
$(".btnSerachButton").click();
}
});
Im using the above code to detect whether the user has typed something in a search box then hit enter instead of pressing the search button. this works for all browsers apart from IE. IE can read the on keyup event but bypasses the if statement used. Any idea why?
There some incompatibility in ie regarding event and keycode so to make it browser compatible try this
$(".tbSearchBox").keypress(function (event) {
var ev = event || window.event;
var key = ev.keyCode || ev.which || ev.charCode;
if (key == 13) {
ev.preventDefault();
alert("ye");
searchSet = $(this).val();
$(".btnSerachButton").click();
}
});
var code = (event.keyCode ? event.keyCode : event.which);
or maybe even
var code = event.keyCode || event.which;
You should use event.which here to normalise event.keyCode and event.charCode:
if (event.which == 13) ...
I want to get the keyboard typed text, not the key code. For example, I press shift+f, I get the "F", instead of listen to two key codes. Another example, I click F3, I input nothing. How can I know that in js?
To do it document-wide, use the keypress event as follows. No other currently widely supported key event will do:
document.onkeypress = function(e) {
e = e || window.event;
var charCode = (typeof e.which == "number") ? e.which : e.keyCode;
if (charCode) {
alert("Character typed: " + String.fromCharCode(charCode));
}
};
For all key-related JavaScript matters, I recommend Jan Wolter's excellent article: http://unixpapa.com/js/key.html
I use jQuery to do something like this:
$('#searchbox input').on('keypress', function(e) {
var code = (e.keyCode ? e.keyCode : e.which);
if(code == 13) {
//Enter keycode
//Do something
}
});
EDIT: Since you're not binding to text box use:
$(window).on('keypress', function(e) {
var code = (e.keyCode ? e.keyCode : e.which);
if(code == 13) {
//Enter keycode
//Do something
}
});
http://docs.jquery.com/Main_Page
You can listen for the onkeypress event. However, instead of just examining either the event.keyCode (IE) or event.which (Mozilla) property which gives you the key code, you need to translate the key code using String.fromCharCode().
A good demo is at Javascript Char Codes (Key Codes). View the source and look for the displayKeyCode(evt) function.
Additional references: w3schools - onkeypress Event and w3schools - JavaScript fromCharCode() method.
This is too complicated to answer quickly. This is what I use as the definitive reference for keyboard handling. http://unixpapa.com/js/key.html