Macromedia Exchange extension authors have written several important extensions related to proper markup. They include
DMX Tidy ” This is an extension version of Dave Raggett's famous HTML Tidy program, used to tidy up problems in HTML and XHTML, and even convert HTML to XHTML.
Entity Converter ” This extension converts characters into entities, and vice versa.
DOCTYPE Inserter ” Inserts the appropriate DOCTYPE declarations into your documents.
