The Document Type

For some features in MooTools you to have set your HTML's Document Type to Strict. This ensure thats browser quirks are taken care of by the library. Here is the document type you can paste right into your own pages. 

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">

The Strict Document Type is recommended even if none of the features you use require it, since it ensures all browsers render your pages correctly.

If you would like to read more about what Document Types are about and which one to use in a situation, you can read the Fix Your Site With the Right DocType article.

Notes

Don't let people fool you when they say to put the following into your XHTML. 

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html 
     PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">

Don't fall for it. If you put that xml definition before the Document Type, IE6 and probably IE7 will forget your standard compliance you really want.

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