DOMTokenList contains implementation seems wrong

[sandersky]

I believe your contains method for DOMTokenList in classList.js is incorrect. It is checking the Element's className instead of the array of classes. In the event you check if a DOMTokenList contains a string which is a substring of a class, it would return true when I believe it should return false. Instead it should be something like:

  contains: function(token) {
    return prototype.indexOf.call(this, token) != -1;
  },

[jerone]

Apparently this was previous the way it worked before removing it after having problems with IE8's fireEvent: 898b546
Array.prototype.indexOf() is only supported since IE 9.

[sandersky]

Well I still think the current implementation is wrong. If I have an element with the class items and check that the element contains the class item it will return true because item is a substring of items while the class item doesn't actually exist on the element.

[jerone]

@sandersky commented on 26 aug. 2014 21:09 CEST:

Well I still think the current implementation is wrong. If I have an element with the class items and check that the element contains the class item it will return true because item is a substring of items while the class item doesn't actually exist on the element.

Seems a valid bug, you're right.

Wish above commit had a bug report attached to it; searching the Internet didn't find any similar issues with Array.prototype.indexOf() and IE's fireEvent.

Edit:
Found the corresponding PR, but no real explanation.

[sandersky]

For me I only care about IE9 and above since IE8 is no longer supported by Microsoft (since April when they stopped XP support). With this being said I opted for the indexOf solution in my project. If I find time I'll submit an IE8 friendly fix to the issue I addressed.