About Roundtrip HTML

Roundtrip HTML is a unique feature of Dreamweaver that lets you move your documents back and forth between a text-based HTML editor and Dreamweaver with little or no effect on the content and structure of the document's original HTML source code. Dreamweaver even maintains and renders some HTML that is technically invalid (such as a FONT tag wrapped around multiple P tags) if such code is supported by browsers. However, the HTML source code that Dreamweaver generates as you edit graphically is always technically valid.

The following are key features of Roundtrip HTML:

	By default, Dreamweaver rewrites overlapping tags, closes open tags that aren't allowed to remain open, and removes extra closing tags when you switch back to Dreamweaver from an external HTML editor or when you open an existing HTML document. If you don't want Dreamweaver to rewrite any source HTML, choose Edit > Preferences, then select HTML Rewriting to turn off all rewriting. See HTML Rewriting preferences.
	Dreamweaver displays markers in the document window for invalid HTML that it does not support. The invalid tags are highlighted in yellow. When you select an invalid tag, Dreamweaver displays information in the Property inspector about how to correct the error. If you turn off HTML rewriting, any HTML that Dreamweaver would have rewritten is displayed as invalid.
	Dreamweaver does not change tags that it does not recognize—including XML tags—because it has no criteria by which to judge them valid or invalid. If an unrecognizable tag overlaps a valid one, Dreamweaver may mark it as erroneous but does not rewrite the code. For example, the custom tag in the following would be marked erroneous: <MyNewTag><b>text</MyNewTag></b>.
	Dreamweaver does not alter ColdFusion Markup Language (CFML) or Microsoft Active Server Page (ASP) tags, and it displays icons to identify blocks of CFML or ASP code in the Document window whenever possible. See Editing ColdFusion and Active Server files in Dreamweaver.
	Dreamweaver lets you launch a text-based HTML editor to edit the current document. Dreamweaver is integrated with HomeSite (Windows) and BBEdit (Macintosh). See Using external HTML editors.