undefined is null

Doing a "very bad thing", as according to Microsoft, often has consequences. The other day I tried to add a column to a list in the Sharepoint site I am developing. The form failed, with an error message that "undefined was null".

Huh?

Not one of the more informative messages you could get. Until I started to think it through a little bit. Not only was a variable lacking content ("null"), but the variable itself was missing ("undefined"). This put me on the thread of a passing mention in the article I had based some of my Sharepoint hackery on.

This article was "One Master to Rule Them All", which proposed and illustrated a means of redirecting requests for application.master in WSS and MOSS from the stock file to your own customized version.

In the article, David Wise mentioned that you should, in your customized application.master file:

"Throw any ContentPlaceHolders that you are not using in a hidden DIV at the bottom of the page - but before the closing FORM tag (the only exception to this seems to be "PlaceHolderUtilityContent" which goes in after the closing form tag)..."

Once I tracked down this article, which was the one I vaguely remembered having a warning about placement of a particular contentplaceholder on an application.master page, I reviewed my own application.master page and found that, yes indeedy, I had put the placeholderutilitycontent contentplaceholder in the hidden div rather than immediately after the form closing tag.

Once I changed the file to put the contentplaceholder immediately after the tag, adding the custom column to the list worked just fine.

Phew. I didn't have to go back to square one with the site design like I feared I might when I first ran into this error.