Client validation in FF

Recently, I have to fix a bug where client validation doesn’t work in FF.

Finally, i notice that the problem exist in web.config which tells to force xhtmlConformance mode=”legacy”

1:
This will render the validation attribute

1:
2: 3: controltovalidate="text1"
4: id="required1"
5: evaluationfunction="RequiredFieldValidatorEvaluateIsValid"
6: validationgroup="grp1"
7: initialvalue=""
8: style="color:Red;visibility:hidden;">required
Instead of this

1: 2: yle="color:Red;visibility:hidden;">required
3:
4:
The reason why it doesn’t work is EXPANDO.

When tracing in the debugger, you can see that the expando properties are
not recognized, though they do exist in the "attributes" collection.
Expando attributes are fine in Firefox, but cannot be accessed as if they
are a part of the DOM as IE allows. Any attribute that is not part of the
DOM is only accessible via obj.getAttribute('x') or obj.attributes['x'].value.

The ASP.NET 2.0 client script library needs to be updated to avoid the
DOM-like property access to expando attributes. Instead, use getAttribute().
Some links re expandos:
http://msdn.microsoft.com/library/default.asp?url=/workshop/author/dhtml/referen
ce/properties/expando.asp
http://www.xulplanet.com/ndeakin/archive/2004/9/12/
http://www.howtocreate.co.uk/tutorials/javascript/dombasics
Also, all HTML attributes are supposed to be caseless, so
and are identical. However IE 6 treats them as two
different attributes, so be sure that all references are in lowercase!