Why does Firebug return an error in my doctype?
DOCTYPE normally is expressed on one line like below. and can cause syntax error
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
But even sometimes it will yell about a syntax error when a src attribute is not declared for an element. Firebug can also through this error when a source is not found or is called twice on one page. EX: script/image/link.
This usually happens because you are loading an HTML document as a script. This is often caused by <script src=""></script>
(i.e. a relative URI pointing at the current, HTML, document)) or one of the scripts pointing to a 404 error.