Disable alert();

Question

Code that is generated on my page that I cannot control contains an alert. Is there a jQuery or other way to disable alert() from working?

The javascript that is being generated that I want to disable/modify is:

function fndropdownurl(val)
1317 { var target_url
1318 target_url = document.getElementById(val).value;
1319 if (target_url == 0)
1320 {
1321 alert("Please Select from DropDown")
1322 }
1323 else
1324 {
1325 window.open(target_url);
1326 return;
1327 }
1328 }

I want to disable the alert on line 1321

Thanks

See [JavaScript: Overriding alert()](http://stackoverflow.com/questions/1729501/javascript-overriding-alert) — Andrew Moore, Dec 08 '10 at 14:01

score 111 · Accepted Answer · answered Dec 08 '10 at 13:58

111

Simply overwrite alert with your own, empty, function.

window.alert = function() {};

// or simply
alert = function() {};

answered Dec 08 '10 at 13:58

Andrew Moore

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2

The second version won't work in IE. Stick to the first. – Tim Down Dec 08 '10 at 14:01
1

The first one works cross-browsers, Thanks! – specked Dec 08 '10 at 14:07
3

how to enable it again? – Nk SP Aug 06 '14 at 12:22
3

@NkSP I think you might be able to re-enable it by running `delete window.alert` or just `delete alert` (both worked for me in Chrome console). I think that would remove your empty function and leave the native function working as expected. – Buttle Butkus Oct 25 '14 at 08:28
`delete window.alert` doesn't work for me, but this yes it does: http://stackoverflow.com/a/10267075/454827 – ZiTAL Jan 11 '17 at 14:26

joar · Answer 2 · 2011-08-12T14:37:37.330

21

This works in Chrome and other browsers with the console.log function.

window.alert = function ( text ) { console.log( 'tried to alert: ' + text ); return true; };
alert( new Date() );
// tried to alert: Wed Dec 08 2010 14:58:28 GMT+0100 (W. Europe Standard Time)

edited Aug 12 '11 at 14:37

answered Dec 08 '10 at 14:00

joar

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Indeed, if you avoid the default behavior of alert() it is a good idea to at least output alert() calls to console.log(). Just overriding alerts puts you on a much more obscure scenario. Your code can fail and because you supressed al alerts (that may contain important info) you may be never acknolowedged. Cool. – m3nda Feb 18 '18 at 15:46

score 9 · Answer 3 · answered Dec 08 '10 at 13:56

9

You can try and make a new function function alert() { } , this is not going to do anything since is empty and will overwrite the existing one.

answered Dec 08 '10 at 13:56

Vlad.P

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score 6 · Answer 4 · answered Dec 08 '10 at 13:56

6

Try this:

alert("test");
alert = function(){};
alert("test");

The second line assigns a new blank function to alert, while not breaking the fact that it is a function. See: http://jsfiddle.net/9MHzL/

answered Dec 08 '10 at 13:56

James Wiseman

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Disable alert();

4 Answers4

Linked

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