SharePoint Custom Datasheet Mode – IE Crash

There is a known SharePoint customization bug that under certain circumstances, modifications to a master page (ie, use of a doctype or margin/padding) will cause the “Edit in Datasheet” mode to crash Internet Explorer.

The underlying problem is caused by a poorly written function called GCComputeSizing within Core.js The common fix is to override this function by defining your own function called GCComputeSizing in a script reference that is loaded in after the reference to Core.js is called in your master page.

However, what most of the other blogs and resources fail to mention is that Core,js can sometimes be loaded in using the “defer” attribute of the script tag. When this happens, core.js will now be loaded in after the page is loaded. Unless you also defer your override script, you will invoke the built-in GCComputeSizing function and the bug will persist.

This problem was specifically noticed when using user-defined or custom datasheet views. Comparing the source html for standard and custom datasheet view yieled the following:

Standard Datasheet View:
<script type=”text/javascript” language=”javascript” src=”/_layouts/1033/core.js”></script>

Custom Datasheet View:
<script type=”text/javascript” language=”javascript” src=”/_layouts/1033/core.js” defer></script>

As you can see, only custom datasheet views were loading in core.js  as a deferred script. Adding the defer attribute to our custom override script fixed this problem by deferring the override after the deferred core.js was loaded.

In terms of overriding GCComputeSizing  there are many examples easily searchable through the interwebs. One word of caution though, as a person who has quite a bit of experience with Javascript, GCComputeSizing not a function suitable for production. Even some of the *corrected* versions that others have posted still make me uneasy. Anything that has the potential of throwing a client’s browser into an infinite loop and locking up their cpu is a serious  cause for concern. Fortunately, our customized design uses a fixed layout so I was able to simplify GCComputeSizing to the following:

function GCComputeSizing(GCObject)
{
    if (TestGCObject(GCObject))
    {
      var lGCWindowWidth=663;
      var lGCWindowHeight=550;

      glGCObjectWidth = lGCWindowWidth;
      glGCObjectHeight = lGCWindowHeight
    }
}