Error on using alert in Javascript (Property 'alert' of object is not a function)

Question

I am just trying to use alert and put a string variable inside the alert and get an error:

Uncaught TypeError: Property 'alert' of object [Object Window] is not a function

My code is:

var shortenurl = msg.d;
alert(shortenurl);

I've checked the value and it has a string inside, not an object.

score 45 · Answer 1 · answered Jul 04 '12 at 19:34

45

Somewhere in your code you overrode alert. Check for var alert = ... or some other kind of declaration like that. Also check for window.alert declarations.

answered Jul 04 '12 at 19:34

Chris Laplante

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3

Possibly not `var` but simply `alert = "whatever";`. – VisioN Jul 04 '12 at 19:34

score 23 · Accepted Answer · answered Jul 24 '13 at 12:12

23

I had that error message due to an alert() blocked by my pop-up-blocker.

answered Jul 24 '13 at 12:12

Lester

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Wow man, thanks a lot... would have bever tought about that ;) – Sagive Oct 09 '13 at 14:33

score 6 · Answer 3 · answered Mar 15 '13 at 23:37

6

I'm adding this one as an addition to this. In my case, when I had a similar problem, it turned out to not be my own code that was causing the problem but a poorly written extension that had been added to a client's browser. Once it was disabled, the script error went away.

If you haven't overridden the method name in your own code anywhere, you may want to try disabling extensions to see if any of those is inadvertently interfering with your script.

answered Mar 15 '13 at 23:37

Rob Wilkins

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Yeah that was my problem too. In Chrome, Ctrl+Shift+N to jump into an incognito window. Run a test in there. Also, if this is the case, you'll notice that alert() fails on every site, not just what you're working on. – Ev. Apr 19 '13 at 05:15
Yeah, i had a popup blocker, which was disabling alerts. I disabled that extension in chrome and now it works fine – Nanu Jul 11 '13 at 19:54

score 4 · Answer 4 · answered Jul 25 '17 at 12:54

4

Check if you've got a Bootstrap .js declaration if required (after jQuery) i.e.

<script src="//code.jquery.com/jquery-1.11.0.min.js"></script>
<script src="//maxcdn.bootstrapcdn.com/bootstrap/3.3.2/js/bootstrap.min.js"></script>

answered Jul 25 '17 at 12:54

WojCup

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4

score 1 · Answer 5 · answered Nov 07 '19 at 16:06

1

Adding to Chris's answer... I had mistakenly overrode alert in my own function!

    //Don't do this:
    function alertOrConsole(node, alert){
        if(alert){
            alert(node);
        }else{
            console.log(node);
        }
    }

   //----------------------------
   //Fixed:
    function alertOrConsole(node, flag){
        if(flag){
            alert(node);
        }else{
            console.log(node);
        }
    }

answered Nov 07 '19 at 16:06

Petro

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This! Or as in my case, a state hook in React called alert: const [alert, setAlert] = usestate(null); – Washbear Apr 04 '23 at 09:26
Brilliant! lol – Petro Apr 04 '23 at 15:42

score 1 · Answer 6 · answered Mar 28 '22 at 20:07

1

One of the possible reasons could be that alert is used as variable - for example inside of function:

function MyFunction(v1,alert) { alert(v1); //will fail exactly with that message }

Solution is not to use predefined words as variables.

answered Mar 28 '22 at 20:07

user18612028

11
1

helped this tip. – Abdul azeez VP Jun 01 '23 at 11:30

score 0 · Answer 7 · answered Feb 20 '14 at 14:27

Mozilla says,

The alert function is not actually a part of JavaScript itself.

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Introduction_to_Object-Oriented_JavaScript

You can not see a function called alert here : https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects

Error on using alert in Javascript (Property 'alert' of object is not a function)

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