When converting my site to XHTML, the WordPress plugin “WP GuestMap” posed another little obstacle. It is the plugin that I use on the “Visitors” page to display the world map with the hometowns of all visitors.
Until now, I had implemented the map via IFrame. Although the plugin does offer a code snippet for XHTML-conform embedding as an object, it just didn’t work in Firefox: Instead of a map, it displayed – nothing. The code looked as follows:

After I had finally struggled through an article on AListApart.com:”Flash Satay: Embedding Flash While Supporting Standards(AListApart.com)”:http://www.alistapart.com/stories/flashsatay that I had delayed reading for weeks already, I knew what the snag was: It was the attribute classid that caused the trouble!

(…) the GUID used in the classid attribute was specific to the browser’s ActiveX configuration. In fact, it was causing Netscape 7 and Mozilla to totally ignore the object.

To say it clearly: classid is only for Internet Explorer, to let it know which player/program it should use to play back/display the object. There is, however, another attribute for the very same purpose which is understood by all browsers, namely the type attribute. As you can see, the code generated by “WP GuestMap” already contains a type declaration. So what’s the point of the totally superfluous classid? Hence with it!

And now it works in Firefox, too! This little knack is not only helpful with HTML objects like this one, but with all the others as well. Only the type statement must be changed. For a Flash object for example, it would have to be type="application/x-shockwave-flash".