E.g.
To get a copy of this page that works locally, use View->Source, then copy and paste the html text into a local .html file. (If you use File->Save As..., your browser may not save the correct header information.) Check that your file is viewable with Netscape 7+ (or other Gecko based browsers) as well as with IE+MathPlayer on MS Windows.
Technical Note: this method of displaying MathML in Netscape/Mozilla/Firefox does not recognize all entity names in the MathML DTD, but only those that are in the HTML DTD (see HTMLsymbol.ent or HTMLsymbol.ent.txt). To get access to all symbols, use numeric entity names (e.g. ∮ for ∮).