HTML doesn't have escape characters (as it doesn't use escape-semantics for reserved characters, instead you use SGML entities: &
, <
, >
and "
).
SGML does not have a named-entity for the tab character as it exists in most character sets (i.e. 0x09
in ASCII and UTF-8), rendering it completely unnecessary (i.e. simply press the Tab key on your keyboard). If you're working with code that generates HTML (e.g. a server-side application, e.g. ASP.NET, PHP or Perl, then you might need to escape it then, but only because the server-side language demands it - it has nothing to do with HTML, like so:
echo "<pre>\t\tTABS!\t\t</pre>";
But, you can use SGML entities to represent any ISO-8859-1 character by hexadecimal value, e.g. 	
for a tab character.