button onclick event handler

[moondaddy]

I have an asp.net 2.0 application and put a html button on a web page. I
double clicked on the button and it crated the event handler for me and
created the stub js function for it like this:

<input id="btnQryFunctions" type="button" value="Query Functions"
language="javascript" onclick="return btnQryFunctions_onclick()" />

and the function it created was:

function btnQryFunctions_onclick() {

}

Question: why did it create this code? onclick="return
btnQryFunctions_onclick()"

Normally I would have just written: onclick="btnQryFunctions_onclick()" with
out the 'return'. What does the word 'return' do for me in this case?

Thanks.

 

[Guest]

Hi,

In this case, it indicates that the function 'btnQryFunctions_onclick()'
will return a boolean value based on which the form will be submitted back.

For example, you might have some validation script within
'btnQryFunctions_onclick()' script function that. In case the validation
fails and you do not want the form to be submitted, you can return false
which will not let the form to be submitted.

Regards,
Augustin
http://augustinprasanna.blogspot.com

 

[Steven Cheng[MSFT]]

Hello Moondaddy,

I think difference here is the button you added is a html submit button
rather than ASP.NET server button. so the "" event handler you see here is
a client-side script rather than server-side event handler.

===========
<script language="javascript" type="text/javascript">
// <!CDATA[

function Submit1_onclick() {

}

// ]]>
</script>
====================

And in client-side script event hander, we can stop the event by return
false in event handler, that's why the auto-generated "onclick" attribute
is like below:

onclick="return function_hander();"





If you add a ASP.NET server button and double click it, it will add an
server-side event handler in code-behind. and this code is executed at
server-side after postback and haven't return type.

Hope this help clarify this. If you have anything unclear, please feel free
to post here.



Sincerely,

Steven Cheng

Microsoft MSDN Online Support Lead



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