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Alert when backspace is pressed inside textbox

I have a grid with three read-only columns. Whenever user goes in there and try to edit by pressing backspace, I need to alert by giving a message. I am using this script and it doesn't work? Can anyone correct me?
$(document).ready(function () {
$('#txtCode').bind('keypress', function (e) {
if (e.which == 8) {
alert('The column is read-only and is not editable');
}
}
});

instead of keypress try with keyup or keydown with .on() method:
$('#txtCode').on('keyup keydown', function (e) {
You can bind multiple events like this too.
and one more thing closing of $('#txtCode') seems to be missing });
$(document).ready(function () {
$('#txtCode').on('keyup keydown', function (e) {
if (e.which == 8) {
alert('The column is read-only and is not editable');
}
}); //<----");" this is the closing you misssed this
});
See the fiddle in action

If this is all the code you are testing, you weren't closing the function properly, annotated in my posted code. Also use keyup instead of keypress
$(document).ready(function () {
$('#txtCode').bind('keyup', function (e) {
if (e.which == 8) {
alert('The column is read-only and is not editable');
}
}); /*<-- You weren't closing your function properly*/
});
Fiddle
You do indeed need to add a return false statement to ensure the character doesn't get deleted anyway. I also took it a step further and extended jQuery with a preventKeyUsage method.
$(document).ready(function () {
$.fn.preventKeyUsage = function (key, message) {
return this.each(function () {
$(this).on('keydown', function (e) {
return (e.keyCode === key) ? (function () {
alert(message);
return false;
})() : true;
});
});
};
$('#txtCode').preventKeyUsage(8, 'The column is read-only and is not editable');
});
New Fiddle

Working code is:
Java Script Code:
$(document).ready(function () {
$('#txtCode').bind('keypress keydown', function (e) {
if (e.which == 8) {
alert('The column is read-only and is not editable');
}
});
});

Here is the updated code
<input type="text" id="txtCode" />
$(document).ready(function () {
$('#txtCode').bind('keydown', function (e) {
if (e.which == 8) {
alert('The column is read-only and is not editable');
return false;
}
});
});
Fiddle Demo

Try this
$(document).ready(function () {
$('#txtCode').on('keyup', function (e) {
if (e.which == 8) {
alert('The column is read-only and is not editable');
}
});
});
DEMO (Working on Firefox & Chrome)

$('#textbox').keydown(function(event){
if(event.keyCode == 8){
alert("Backspace not allowed..");
return false;
}
});
http://jsfiddle.net/xF9jL/1/

You are missing }); of keypress. google chrome have issues with keypress, u can try keydown instead
$(document).ready(function () {
$('#txtCode').bind('keydown', function (e) {
if (e.which == 8) {
alert('The column is read-only and is not editable');
}
});
});
To use delete ,arrows, backspace keys in Chrome you must use keydown. keypress on these keys work only in Firefox and Opera.
DEMO

You can probably solve the underlying issue by either not using an element that accepts input, or by using the disabled attribute:
<textarea name="example" disabled>Some text</textarea>
If you are posting back to the sever, you should assume the user has edited the field, no matter what you do to prevent it.

keypress event won't give keycodes for all keys in all browsers . Better use keyup or keydown event which gives keycode for all keys in all browsers
In order to understand the difference between keydown and keypress, it is useful to understand the difference between a "character" and a "key". A "key" is a physical button on the computer's keyboard while a "character" is a symbol typed by pressing a button. In theory, the keydown and keyup events represent keys being pressed or released, while the keypress event represents a character being typed. The implementation of the theory is not same in all browsers.

using .keypress and .keydown side by side

I need to capture normal text with upper and lower case letters, but I also want to pick up the key codes for alt, ctrl, esc, etc. I have attempted to run the two jquery functions .keypress and .keydown, and only accept special keys from .keydown, but when they are together, they only give to result of one. I am using Chrome, but I also need support for as many other browsers as possible.

You can fetch the state of special keys using jQuery.Event which is the first argument of the callback from a listener:
http://jsbin.com/epuqig/2/embed?live
jQuery(function($) {
$('input').on('keydown', function(event) {
// event.shiftKey
// event.ctrlKey
// Also to fetch the keyCode use:
// event.which
if ( event.which == 8 && event.shiftKey ) {
// Backspace and shift key is pressed
}
});
});
You can go vanilla if you don't care about old browsers:
window.addEventListener('load', function() {
var inputs = document.querySelectorAll('input');
[].forEach.call(inputs, function(input) {
input.addEventListener('keydown', keydownHandler, false);
});
}, false);
function keydownHandler(event) {
if ( event.keyCode == 8 && event.shiftKey ) {
// Backspace and shift key is pressed!
}
}
As you can see this is almost the same code snippets but the second one want work in < IE9

$(document).ready(function () {
$(document).keydown(function (e) {
var code = e.keyCode;
if(e.altKey) // you can also use - e.ctrlKey , e.shiftKey
// alt key
}).keyup(function (e) {
var code = e.keyCode;
});
});

Bind enter key to specific button on page

<input type="button" id="save_post" class="button" value="Post" style="cursor:pointer;"/>
How can I bind the enter key on the persons keyboard to this specific button on the page? It's not in a form, and nor do I want it to be.
Thanks!

This will click the button regardless of where the "Enter" happens on the page:
$(document).keypress(function(e){
if (e.which == 13){
$("#save_post").click();
}
});

If you want to use pure javascript :
document.onkeydown = function (e) {
e = e || window.event;
switch (e.which || e.keyCode) {
case 13 : //Your Code Here (13 is ascii code for 'ENTER')
break;
}
}

using jQuery :
$('body').on('keypress', 'input', function(args) {
if (args.keyCode == 13) {
$("#save_post").click();
return false;
}
});
Or to bind specific inputs to different buttons you can use selectors
$('body').on('keypress', '#MyInputId', function(args) {
if (args.keyCode == 13) {
$('#MyButtonId').click();
return false;
}
});

Vanilla JS version with listener:
window.addEventListener('keyup', function(event) {
if (event.keyCode === 13) {
alert('enter was pressed!');
}
});
Also don't forget to remove event listener, if this code is shared between the pages.

Maybe not quite what you're looking for but there is a HTML property that lets you assign a specific button called an access key to focus or trigger an element. It's like this:
<a href='https://www.google.com' accesskey='h'>
This can be done with most elements.
Here's the catch: it doesn't always work. for IE and chrome, you need to be holding alt as well. On firefox, you need to be holding alt and shift (and control if on mac). For safari, you need to be holding control and alt. On opera 15+ you need alt, before 12.1 you need shift and esc.
Source: W3Schools

Overwriting key events

How to overwrite or remove key events, that is on a website? I'm writing a script for GreaseMonkey and I want to make event on Enter button, but when I press the ENTER button, it triggers function on website.
EDIT 1: Here is the website, that I need to do this http://lockerz.com/auth/express_signup

One of these two should do it for you. I used the first one, although someone on SO told me the second one will work also. I went for the hammer.
Sorry, first one wasn't a cut and paste answer. I use using it to return up/down arrow control on a website. I changed it so that it identifies keycode 13 instead.
(function() {
function keykiller(event) {
if (event.keyCode == 13 )
{
event.cancelBubble = true;
event.stopPropagation();
return false;
}
}
window.addEventListener('keypress', keykiller, true);
window.addEventListener('keydown', keykiller, true);
})();

Searching quickly on SO:
jQuery Event Keypress: Which key was pressed?
Code from there:
var code = (e.keyCode ? e.keyCode : e.which);
if(code == 13) { //Enter keycode
//Do something
}

Without a library, use: http://jsfiddle.net/4FBJV/1/.
document.addEventListener('keypress', function(e) {
if(e.keyCode === 13) {
alert('Enter pressed');
return false;
}
});

Combination of Keypresses using JS / jQuery ( Escape & Shift +Escape )

Is there a way in js/jQuery how to have these two combinations of keypresses?
ESCape key
and
SHIFT + ESCape key
when I implemented it using:
document.onkeydown = function(e){if (e == null) {keycode = event.keyCode;}
else {keycode = e.which;}
if(keycode == 27){closeAll();}}
//upon pressing shift + esc
$(document).bind('keypress',function(event)
{
if(event.which === 27 && event.shiftKey)
{
closetogether();
}
});
The escape button works perfectly but the one with the shift + esc is getting confused I think because it's doing nothing. Don't worry the function works as when I change the combining key 27 to 90 (z) for example it works just fine.
Can someone opt me for a better way ?

Why don't you bind the keydown event using jQuery? That way you would already have a normalized event variable. You can also check the status of the shift key in the same handler.
These events send different keycodes back. Use keyup/keydown for capturing certain keys by scancodes and use keypress to capture actual text input by characters.
$(document).bind('keydown', function(event) {
if(event.which === 27){
if(event.shiftKey){
closetogether();
} else {
closeAll();
}
}
});