1121945 - Mismatch for <input pattern="\S+">

Status: RESOLVED INVALID

(Core :: DOM: Core & HTML, defect)

Description

[David Bruant]

Not sure what the proper component is. I did my best. Change component as you find appropriate.

Steps to reproduce:
1) Create a document with <input pattern="\S+">
2) type " a" (space followed by the letter "a")
3) remove focus from the input

What happens:
The value is considered invalid

Expected:
The value should be a valid given " a".match(/\S+/) doesn't return null (and the pattern attribute is supposed to follow JavaScript regexps)

Comment 1

[Boris Zbarsky [:bzbarsky]]

Looking at our pattern attribute handling, it takes the value of the pattern attribute and prepends "^(?:" to it and appends ")$" to it.  Clearly /^(?:\S+)$/ doesn't match " a".

The relevant spec is at https://html.spec.whatwg.org/multipage/forms.html#the-pattern-attribute and says:

  The compiled pattern regular expression, when matched against a string, must have its
  start anchored to the start of the string and its end anchored to the end of the 
  string.

and then has an informative note:

  This implies that the regular expression language used for this attribute is the same
  as that used in JavaScript, except that the pattern attribute is matched against the
  entire value, not just any subset (somewhat as if it implied a ^(?: at the start of
  the pattern and a )$ at the end).

Comment 2

[David Bruant]

I should have read the spec first, sorry :-s

pattern="\s*(\S+\s*)+" does the job