[whatwg] Web Forms: pattern attribute

Michel Fortin michel.fortin at michelf.com
Mon Apr 3 15:04:17 PDT 2006

Something about the pattern attribute in Web Forms got me thinking:

> The regular expression language used for this attribute is the same  
> as that defined in [ECMA262], except that the pattern attribute  
> implies a ^ at the start of the pattern and a $ at the end (so the  
> pattern must match the entire value, not just any subset).

Does that mean that a pattern attribute like "foo|bar" should  
translate to /^foo|bar$/ ? Wouldn't it make more sense it it was /^ 
(foo|bar)$/ with the parentesis?

Because in the first case it would match either something that begins  
by "foo" (like "football") or ending with "bar" (like "babar"). In  
the second case it would match only "foo" or "bar", nothing else. The  
later interpretation seems more in line with the intent, but I  
suppose this could be made clearer.

Michel Fortin
michel.fortin at michelf.com

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