cancel postback from javascript on confirm popup

Question

Following this problem ASP.NET: OnServerClick event handler not called if using onclick

I implemented a workaround:

<button id="idBtnPrint" runat="server" type="submit" onserverclick="BtnPrint_Click" onclick="confirmImpression();">print</button>

javascript function:

    function confirmImpression() {

        if (!confirm("sure ?"))
            arg.whatever;

    }

where confirmation is positive the postback is started when cancel the postback is not run (as I want) simply because an error generated js "arg is undefined" (normal because arg is not instanciate) script is locked and therefore no postback (as I want too).

but how to do this properly. I would not see the error appear in the status bar in the browser.

any suggestion is welcome!

thank you

score 11 · Answer 1 · answered Dec 08 '11 at 22:54

I ran into a problem very similar to this, and even though this question is old, I thought my answer might help someone down the road. When you have a javascript method that is supposed to return something and you place it in the OnClientClick, it still doesn't return what the method really returns. In order to fix this issue, you have to return the method in the OnClientClick.

OnClientClick="return MethodName()"

You also need to make sure that your method is returning the correct true/false from the confirmation dialog.

function MethodName() {
    if (!confirm('Are you sure you want to X?')){
         return false;
    }
    else{
         return true;
    }
}

tvanfosson · Accepted Answer · 2010-07-03T14:49:51.567

Simply wrap the confirmation in an if-block and return false if the confirmation fails. The standard javascript that generates the postback will be appended to the check and thus be run if the action is confirmed.

<button id="idBtnPrint" runat="server" type="submit"
        onserverclick="BtnPrint_Click"
        onclientclick="if (!confirm('sure ?')) { return false; }">print</button>

The reason that arg is undefined is that you don't use it as an argument nor is it defined in the window object. I assume that you're trying to hook into the validation system, but it won't work in this case because the validation logic isn't being invoked. You simply want to stop execution of the client-side handler if the user answers in the negative and the above code will do that.

Though the answer in the referenced question will work as well I prefer to use a full javascript statement to aid in understanding what is going on.

I know why arg is undefined, but this error cancel the postback, and it is a workaround for me, and it suits me, but I do not want to see the error in the browser in the status bar. — TimeIsNear, Jul 03 '10 at 14:56
@user did you try my suggested code? It will cancel the post back if the user responds negatively without any javascript errors. — tvanfosson, Jul 03 '10 at 16:40

score 3 · Answer 3 · answered Jul 03 '10 at 14:46

3

You want to use OnClientClick and just return the opposite of what the confirm returns...

<button ... onclientclick="return !confirm('Are you sure ?');">print</button>

answered Jul 03 '10 at 14:46

Andir

2,063
1
15
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That won't work as the javascript that does the actual postback gets appended to the client-side click handler, thus causing the problem he's attempting to avoid. – tvanfosson Jul 03 '10 at 14:50
clicking ok or cancel, the postback is never called – TimeIsNear Jul 03 '10 at 14:53

cancel postback from javascript on confirm popup

3 Answers3

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