If you wanted to create a hyperlink to a file called “Me & You”, which of the following should you use?

<a href="Me & You"> or 

<a href="Me &amp; You"> In other words, should you escape the ampersand or not? It depends. If you create a plain HTML page, you must not escape the ampersand or it won't work (browser dependent obviously), however if you leave it unescaped it will work in every browser. If however, you create an XHTML document you should escape the ampersand, otherwise XML parsers will break when parsing the document and browsers will get the link right as long as they are kicked into XHTML mode by the appropriate declaration at the top of the file. If you want to test this try linking to an URL with 

& in it (ie: the file name literally includes the HTML entity for ampersand). Better yet, don’t put stupid characters in your URLs.