asp.net / javascript not generate __dopostback

Question

Some times my portal not generate this function on client side:

    <script language="javascript" type="text/javascript">

function __doPostBack(eventTarget, eventArgument) {
    var theform;
    if (window.navigator.appName.toLowerCase().indexOf("microsoft") > -1) {
        theform = document.Form1;
    }
    else {
        theform = document.forms["Form1"];
    }
    theform.__EVENTTARGET.value = eventTarget.split("$").join(":");
    theform.__EVENTARGUMENT.value = eventArgument;
    theform.submit();
}

I have my site on Microsoft CMS 2002 with framework 1.0. The problem only exists when i put one flash pop-up on home/index page.

Answer 1

I forced one control on form:

<form id="Form1" method="post" runat="server" >
        <asp:LinkButton ID="RequirePostBackScriptLink" runat="server" style="display:none;" />  
        <table width="1003px" border="0" cellpadding="0" cellspacing="0">
            <tr>

...