Wednesday, 14 November 2007

SharePoint - dragging WebParts causes "object required" Javascript error

I have been working with SharePoint quite a bit over the past few months. At Netstore we are building an AA accessible website for our client using XHTML with a CSS based layout.

I recently came across a problem where I had a WebPartZone in a page, and when I tried to drag the webparts around I get the javascript error "Object Required". Fortunately, a bit of googling led me to this post - CSS causes JavaScript error while moving Web Parts in edit mode where I learned the issue is due to the zones being placed in elements with a CSS style of position:relative.

Unfortunately I had to fix the bug to pass UAT so I was left with two options - either change the CSS to remove the relative positioning or try to fix the JavaScript. Given that we were working with HTML/CSS delivered by an external design agency (which I didn't want to mess with) I decided to go with the latter.

The blog entry indicated that the problem lay in a Microsoft function called MSOLayout_GetRealOffset. This function is defined in <12>\TEMPLATE\LAYOUTS\1033\IE55UP.JS. I didn' t fancy changing this file as it would present a deployment nightmare, but fortunately with JavaScript, you can override a global function by just defining it later on in the HTML. Therefore I was able to redefine this function in my master page and fix the error. Here is the new version of the function:

        <script language="javascript" type="text/javascript">
            function MSOLayout_GetRealOffset(StartingObject, OffsetType, EndParent)
                var realValue=0;
                if (!EndParent) EndParent=document.body;
                for (var currentObject=StartingObject; currentObject && currentObject !=EndParent && currentObject != document.body; currentObject=currentObject.offsetParent)
                    var offset = eval('currentObject.offset'+OffsetType);
                    if (offset) realValue+=offset;
                return realValue;

So if you ever experience the problem, copy and paste this function into your master page file, anywhere after the SPWebPartManager and it should stop.