Content Of Elements Must Consist Of Well-formed Mark-up

So I was asking a question on here, got around to implementing the solution, and it doesn't seem to work particularly well - I keep getting the error 'content of elements must cons

Solution 1:

Does this piece of JavaScript happen to live in a <script> tag in an XHTML page? If so, move it to an external JS file, or use a CDATA section in the script tag.