How to determine if window.confirm() is supported?

Question

I have a mobile website that is used by various devices including some onboard computers running a locked down version of Windows Embedded 7 with IE 7. For some reason that I cannot explain, window.confirm() is broken, yet all other javascript seems to work.

I even added the following check before wiring up the confirm handler, but clicking the link simply does nothing.

        if (window.confirm)
        {
            $(".logoff").click(function () 
            {
                return confirm("Are you sure you want to log off?");
            });
        }

If I remove the click handler, the link functions as normal. Is there a better way to test for confirm() support?

Why not use a custom implementation? Of course it could not return the selection without blocking the browser in a nasty way, but you could easily do it with a callback. — ThiefMaster, Feb 27 '12 at 17:21

score 1 · Answer 1 · answered Feb 27 '12 at 16:33

1

How about:

if ('confirm' in window) {
    $(".logoff").click(function () {
        return window.confirm("Are you sure you want to log off?");
    });
}

Another options would be window.hasOwnProperty('confirm').

answered Feb 27 '12 at 16:33

David Hellsing

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score 1 · Answer 2 · answered Feb 27 '12 at 16:33

1

You could use typeof to check if the window.confirm is a function

answered Feb 27 '12 at 16:33

VirtualTroll

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Nicola Peluchetti · Answer 3 · 2012-02-27T17:21:20.287

1

You could do

if ('confirm' in window && typeof window.confirm === 'function' ) {
    $(".logoff").click(function () {
        return window.confirm("Are you sure you want to log off?");
    });
}

edited Feb 27 '12 at 17:21

answered Feb 27 '12 at 16:34

Nicola Peluchetti

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window.hasOwnProperty('confirm') returns false. – kennebec Feb 27 '12 at 17:17
@kennebec yes it's true, i don't know why. I modified my answer to use in – Nicola Peluchetti Feb 27 '12 at 17:21
1

It seems that `typeof window.confirm` is "object" in IE 7 and 8, but "function" in 9. – jrummell Feb 27 '12 at 18:01

score 1 · Answer 4 · answered Feb 27 '12 at 17:19

1

if(typeof confirm=='function')// window.confirm is defined and a function

answered Feb 27 '12 at 17:19

kennebec

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score 0 · Accepted Answer · answered Feb 28 '12 at 13:51

While the following suggested methods worked in every desktop browser I tested, they all evaluated to true on the device and still didn't display a dialog or navigate to the link in the anchor's href.

if (typeof confirm == 'object')
if ('confirm' in window && typeof window.confirm === 'object')
if (window.confirm)

(In IE 7, typeof somefunction is 'object' instead of 'function')

My solution was to use a jQuery UI Dialog instead, based on @ThiefMaster's suggestion.

How to determine if window.confirm() is supported?

5 Answers5

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