How to Disable Function keys using Javascript?

Question

I'm having a page where i need to disable the Function keys mainly F12(Developertools). I'm showing some sensitive data in the page so at any case i cannot make the users see the html and take the hidden fields. I checked some javascript which is working for almost all the keys except the Function keys like f1, f12 etc.

Is there anyway that i can disable these buttons in the browser?

document.onkeyup = KeyCheck;
function KeyCheck() {
    var KeyID = event.keyCode;
    alert(KeyID);
    switch (KeyID) {
        case 123:  //F12 KEY CODE         
            alert('hello');
            return false;
            break;            
    }

}

This is the code which im using for overriding the key. When I searched, the keycode of F12 key is 123 and im using the same code for overriding it. But unfortunately its not even hitting the "CASE" and the message box is not appearing when pressing F12, F1 etc buttons.

Please Help me in this.

Answer is you shouldn't send sensitive data over the wire. Disabling F12 might disable one way of getting into developer tools on one browser. But what if someone clicks on the menu option? Not to mention the sensitive data is visible to anyone with a little knowhow. — Simon Laing, Dec 03 '12 at 07:26
Even without the console, I could get the data or unhook your protection or hook my own console with Tampermonkey or Greasemonkey easily. — John Dvorak, Dec 03 '12 at 07:28
Even if you disable `F12`, I could press `Ctrl+Shift+I` and not even realise `F12` is disabled. — John Dvorak, Dec 03 '12 at 07:32
@JanDvorak. I guess the OP could also catch `Ctral+Shift+I`, but that could get out of hand soon enough, right? I mean, do the different browsers all have the same key combinations for the consoles? I kinda doubt it. — Cerbrus, Dec 03 '12 at 07:42
@Cerbrus you can kill all shortcuts of the popular five (FF+IE+O+WK) with just `F12, Ctrl+Shift+I and RightClick`, but you can't kill their respective menu items, you can't kill Tampermonkey, you can't kill Fiddler... — John Dvorak, Dec 03 '12 at 07:45
Oh, cross-browser consistency, how refreshing :D I assume you mean chrome with number 5? ;-) — Cerbrus, Dec 03 '12 at 07:48

Cerbrus · Answer 1 · 2012-12-03T07:38:17.387

There is no reliable way to prevent users from tampering with your javascript data, when you've sent it. Always use server-side checks to verify the returned data.

People can still use the browser's menu to enable the dev console. Or through right-click --> "Inspect Element", or by using hotkeys to open different sections of the console, then tabbing to another page in the console, or by using one of the hotkeys I've failed to mention.
Or, they can simply disable javascript. (Or edit the javascript to disable the block)

Now, you can be a little more thorough in disabling whatever button's functionality, by adding a:
event.preventDefault() in your event listener, but still, it's unreliable.

Also, please consider marking this as your answer. I realise it's not exactly the answer you were looking for, but such are the hard facts of a programmer's life: Language dictates (available) functionality. — Cerbrus, Dec 03 '12 at 07:50

score 0 · Answer 2 · answered Dec 03 '12 at 07:24

0

document.onkeydown = KeyCheck;

It worked.

answered Dec 03 '12 at 07:24

smilu

859
7
30
53

It will just override the user from typing those keys. But still they can take some of these information's using menu. – smilu Nov 18 '15 at 06:35

Alexei Levenkov · Answer 3 · 2012-12-03T07:48:25.310

0

No, you can't diasble view source/developer tools or any other application level functionality of the browser via JavaScript on the page.

There are plenty ways to see source of the web page. You are up to very hard task to restrict all external parties to access/store/view your HTML. Here is partial list of other things you'll have to disable:

proxies, including HTTP debuggers/proxies like Fiddler or ones that are built in to browsers.
direct GET requests from console tools like curl.
all sorts of web crawlers, including search engines like Google.

Use HTTPS and do not send sensetive information unless strictly required is the much easier way of protecting it than trying to limit what users can do with their machines.

edited Dec 03 '12 at 07:48

answered Dec 03 '12 at 07:32

Alexei Levenkov

98,904
14
127
179

If only disabling proxies were possible, it'd make IP bans way more reliable :P (Aside from simple IP changes) – Cerbrus Dec 03 '12 at 07:36
@Cerbrus, :) I should also have added search engines (i.e. Google) ... (Obviously +1 to your answer as much more serious). – Alexei Levenkov Dec 03 '12 at 07:43
Hm, I didn't even think about those spiders. Thanks :D – Cerbrus Dec 03 '12 at 07:46

score 0 · Answer 4 · answered Dec 04 '12 at 13:49

0

Try this out:

<script language="JavaScript">
    document.onkeypress = function (event) {
        event = (event || window.event);
        if (event.keyCode == 123) {
           //alert('No F-12');
            return false;
        }
    }
    document.onmousedown = function (event) {
        event = (event || window.event);
        if (event.keyCode == 123) {
            //alert('No F-keys');
            return false;
        }
    }
    document.onkeydown = function (event) {
        event = (event || window.event);
        if (event.keyCode == 123) {
            //alert('No F-keys');
            return false;
        }
    }
</script>

answered Dec 04 '12 at 13:49

Jez

305
2
12

Use `addEventListener` instead of hardcoding the event into the document, also, [DRY](http://en.wikipedia.org/wiki/Don't_repeat_yourself). Initialize the function, then refer to the function by name, in your code. Finally, the `mousedown` event doesn't have a keycode. – Cerbrus Dec 05 '12 at 07:21
I got it from **[here](http://www.enjin.com/forums/m/10826/viewthread/4760201-protect-your-content-disable-rightclick-f12-keys)** by the way... – Jez Dec 05 '12 at 13:40
Then that guy should be smacked on the head for publishing bad code ;-) – Cerbrus Dec 05 '12 at 13:42
But it works, and I guess that's fine. :) And I think I've made a contribution to answer the question "How to Disable Function keys using Javascript?" Just sharing what I found.. – Jez Dec 05 '12 at 13:49

score 0 · Answer 5 · answered Feb 04 '15 at 11:36

This Code works Perfectly for me to Disable Right Click and Disable F12

<script language=JavaScript>

var message="You Have No Permission";


 function clickIE4(){
   if (event.button==2){
     alert(message);
     return false;
   }
 }

 function clickNS4(e){
   if (document.layers||document.getElementById&&!document.all){
     if (e.which==2||e.which==3){
       alert(message);
       return false;
      }
   }
 }

  if (document.layers){
    document.captureEvents(Event.MOUSEDOWN);
    document.onmousedown=clickNS4;
   }
   else if (document.all&&!document.getElementById){
      document.onmousedown=clickIE4;
   }

   document.oncontextmenu=new Function("alert(message);return false")

score 0 · Answer 6 · answered Jul 16 '17 at 16:04

When user press F12 key, browsers developer tool bar will open in the below portion of the browser.

By using the developer tool bar user can see the design, javascript code and corresponding css applied to the controls in the page. To prevent the user to do that we will hide the developer tool bar.

Here is the code

How to Disable Function keys using Javascript?

6 Answers6

Linked