4

In my chat application there are some text fields which gets the user login details.

when filling the user details,If user suddenly pressed the ESC key,the data will be lost.

I need to disable the function of ESC key ? which event I need to use ? how can I do that.

my Java Script code is ,

function esc(e){
    e = e || window.event || {};
    var charCode = e.charCode || e.keyCode || e.which;
    if(charCode == 27){
    return false;
    }
}

Searched a lot in Stack overflow and google.Nothing worked.Please any one help me to do that . Thanks..

Human Being
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4 Answers4

6

You can bind an eventlistener to your input field to catch the Event when Esc is pressed and supress it.

document.querySelector("input").addEventListener("keydown",function(e){
    var charCode = e.charCode || e.keyCode || e.which;
    if (charCode == 27){
         alert("Escape is not allowed!");
        return false;
    }
});

Example

Christoph
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  • Thanks for your reply... nothing happened .any more ideas ? – Human Being Jan 30 '13 at 10:39
  • What exactly do you mean by nothing happens? This code [works perfectly](http://jsfiddle.net/JEhjG/). Did you include this script AFTER your input element? Take a look at the webdeveloper console (press F12) an look for errors. – Christoph Feb 01 '13 at 10:34
  • Thank for your reply...Works in Fiddle but not working in my browser. – Human Being Feb 01 '13 at 11:26
  • @Anand assuming your answer, you are using Internet Explorer. Be aware however, that your code will break in all other browsers! – Christoph Feb 01 '13 at 11:28
  • See the solution which I gave.It works in all browsers.I will debug why your code is not working for me.Any way thanks for your support Mr.Christoph. – Human Being Feb 01 '13 at 11:32
  • Also see my new question in [My new question](http://stackoverflow.com/questions/14645011/window-onbeforeunload-and-window-onunload-is-not-working-in-firefox-safari-o).Help me if possible. – Human Being Feb 01 '13 at 11:34
  • This does not work in full screen mode, it doesn't prevent user to exit full screen... – Gibberish Apr 19 '21 at 08:45
3

I got the solution to control the " F5 , Esc , BackSpace(BS) " keys with the following code.

My Java Script code will be ,

document.attachEvent("onkeydown", win_onkeydown_handler);

function win_onkeydown_handler() {
    switch (event.keyCode) {

    case 116 : // 'F5'
         event.returnValue = false;
         event.keyCode = 0;
         break;  

    case 27: // 'Esc'
        event.returnValue = false;
        event.keyCode = 0;
        break;

    case 08: // 'BackSpace'
        if (event.srcElement.tagName == "INPUT"
                || event.srcElement.tagName == "TEXTAREA") {
        } else {
            event.returnValue = false;
            event.keyCode = 0;
        }
        break;

    }
}

Thanks who are all supported me to do this and for your suggestions.

Human Being
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    you should **NOT** use this code! This only works in Internet Explorer and will fail in all other browsers. The correct way to bind a eventhandler is via `addEventListener` and never via `attachEvent`! – Christoph Feb 01 '13 at 11:13
1

I have used this for a login popup code:

jQuery(document).keyup(function(e){
    if(e.keyCode==27 && popupStatus==1){
    // alert('not allowed !!!');
        // or any other code
     return false;
    }
});
Riju Mahna
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    I guess 'keydown' does not work in Chrome. Better to use 'keyup' instead – Riju Mahna Jan 30 '13 at 10:42
  • Thanks for your support.I dont have knowlede in JQuery.can u please convert it in to JS. – Human Being Jan 30 '13 at 10:43
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    Buddy, this is probably the simplest 2-line code you may get. Why not start with jQyery today !! :) – Riju Mahna Jan 30 '13 at 10:54
  • @Riju You are guessing wrong! How do you come to this assumption? – Christoph Feb 01 '13 at 10:35
  • @Christoph .. No offence... Its just my humble opinion. – Riju Mahna Feb 01 '13 at 10:43
  • @Riju It's not about opinions, it's about facts, and these are either true or false. And I would consider your statement. http://jsfiddle.net/JEhjG/ – Christoph Feb 01 '13 at 10:47
  • @Christoph .. I never questioned your code. all I said that the code that I gave was simpler and smaller. And what harm will the guy get if he learns jQuery ? After all, libraries like these have been developed out of a necessity when plain javascript fails to provide simple solutions, OR a solution at all, for that matter. Again no offense buddy.. :) – Riju Mahna Feb 01 '13 at 11:00
  • @Riju I feel offended in no way. I am just refering to your: "I guess 'keydown' does not work in Chrome." which is plain wrong. I was not questioning your recommendation of jQuery;) – Christoph Feb 01 '13 at 11:10
  • @Christoph.. It was a guess ('I guess'.. ) so its allowed to be wrong ;) – Riju Mahna Feb 01 '13 at 11:13
0

I have done something similar using jquery to limit entry to numbers 

    $(inputBox).keydown(function(event) {
        // Allow only backspace and delete
        var allowed_keys = [
            46, // delete
            8, // backspace
                 ];
        if ($.inArray(event.keyCode, allowed_keys) != -1) {
            // let it happen, don't do anything
        }
        else {
            // Ensure that it is a number and stop the keypress
            if (event.keyCode < 48 || event.keyCode > 57 ) {
                event.preventDefault(); 
            }   
        }
    });
Dave Gill
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