Always close Your HTML Elements Properly

Sep 21, 2010 • ASP.NET • 1 min read

I’ve just had a strange error trying to write a noddy ASP.NET page using Microsoft Ajax. The error itself was Microsoft JScript runtime error: Object required which basically tells you nothing. This error was being thrown in Sys$WebForms$PageRequestManager$_initializeInternal by the line trying to access this._form.onsubmit. It would appear form is null! Looking up the call stack it originated from the Ajax initialize call : _Sys.WebForms.PageRequestManager._initialize(‘scriptManager’, document.getElementById(‘form1’));. It would appear that the form element has not been closed yet and therefore the document.getElementById is searching for something that doesn’t exist.

Ok, that tells me nothing.

Thankfully I had an epiphany which worked (for once!) Spot the difference between this :

<head runat="server">
    <script type="text/javascript" language="javascript" src="GetResource.ashx?../lib/jquery/1.3.2/jquery-1.3.2.js" />
    <script type="text/javascript" language="javascript" src="GetResource.ashx?../lib/jqueryplugins/jquery.blockUI.js" />
    <script type="text/javascript" language="javascript" src="GetResource.ashx?../rms.utility.web.jqueryplugins/jquery.rms.ajaxprogress.js" />
</head>

and this :

<head runat="server">
    <script type="text/javascript" language="javascript" src="GetResource.ashx?../lib/jquery/1.3.2/jquery-1.3.2.js"></script>
    <script type="text/javascript" language="javascript" src="GetResource.ashx?../lib/jqueryplugins/jquery.blockUI.js"></script>
    <script type="text/javascript" language="javascript" src="GetResource.ashx?../rms.utility.web.jqueryplugins/jquery.rms.ajaxprogress.js"></script>
</head>

In fact, it looks like my syntax highlighter I’m using in LiveWriter has spotted the difference too! BasicaLly because I didn’t close the script element with a </script> IE only executed the first javascript fetch, Firefox wouldn’t execute any and Chrome worked!! Go figure!

Post by: Philip Hendry