add methods for managing css class names

Element tests pass in FF2. All I have available at the moment.

tests pass in FF3 and Safari 3.1.1

Before these become API methods, I propose that we change the names to hasClass, addClass, removeClass. The addition of Name in the method names doesn't add semantic value and its more to type - if these methods get widely used in the library itself then that just adds unnecessary size to the library (albeit minor).

As this is pretty common functionality of several existing libraries, I compared this implementation to what is being done in the mootools library and I have a couple of questions:

1) hasClass(Name) is used quite a bit in the add and remove functions, and it seems likely that these methods will start to find widespread use. Without wanting to get into premature optimization, the mootools approach is to use the indexOf String method with an optional separator seems faster:

(code) hasClass: function(element, name) {

return (' '+element.className+' ').indexOf(' '+name+' ');

} (end)

I just profiled the two approaches in FF3 using loops of 10000 iterations and the indexOf approach seems to be somewhat to quite a bit faster - I was getting variable results that didn't always make sense.

2) I don't quite understand how the regex in removeClass works, but the equivalent function in mootools is a bit different and I just want to make sure someone knowledgeable takes a look at the difference to make sure that our function covers all the bases. The mootools regex is:

(code) this.className.replace(new RegExp('(^{|\\s)' + className + '(?:\\s|$)'), '$1').clean() (end)}

taking out the differences, the difference seems to be the addition of '?:' in the last part of the regex and $1 instead of ' '.

functions for managing element class names

Function names updated as suggested by Paul and conferred by others here.

Oh, and I'd say patches for performance can come later.

(In [7579]) Adding functions to manage dom element class names. Use OpenLayers.Element.hasClass, addClass, removeClass, toggleClass for css class name management. r=pagameba,me (closes #1607)