modelpopupextender works fine but
I have used a flash animation clip in my web page. the popup showing behind the flash animation in IE. Is there any way to solving this problem?   In Mozilla firefox works fine, flash animation will hide when popup; Thanks in advance.

Try doing what IE 6 does with dropDownLists when a modalPopup is shown. Hide the object that displays the flash animation. To do this via javascript set the display of the object to none, like this:

objFlash = document.getElementById('flashObject');
objFlash.style.display = 'none';

and then when the modalPopup is closed change it back like this:

objFlash = document.getElementById('flashObject');
objFlash.style.display = 'inline';

How can i call this function from my ModalPopupExtender

failed using onload, plz provide me the method

Hi,

You can make use of add_shown and add_hidden client event to achieve it.

Please try the below code( 'ModalPopupBehavior' is BehaviorID of ModalPopup Control):

        function pageLoad(sender,e)
        {
            $find('ModalPopupBehavior').add_shown(cpc);
            $find('ModalPopupBehavior').add_hidden(cpe)
        }
        function cpc(ev)
        {
            objFlash = document.getElementById('flashObject');
            objFlash.style.display = 'none';
        }
        function cpe(ev)
        {
            objFlash = document.getElementById('flashObject');
            objFlash.style.display = 'block';
        }

Great, it works! 

Thanks Vince

In case anyone else has this same issue, I wanted to post an alternative solution that was better for our situation.  Simply set the wmode parameter for Flash to transparent. Examples:

TRADITIONAL EMBED:
<param name="wmode" value="transparent" />

AC_FL_RUNCONTENT:
AC_FL_RunContent( 'codebase','http://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=9,0,28,0','width','900','height','1000','title','test','src','animation','quality','high','pluginspage','http://www.adobe.com/shockwave/download/download.cgi?P1_Prod_Version=ShockwaveFlash','movie','animation','wmode','transparent' );

SWFObject:
swfobject.embedSWF("animation.swf", "animation", "300", "120", "9.0.0","expressInstall.swf", '', {wmode:"transparent"}, {id:"animation",name:"animation"});