can't read Element.prototype in firefox

Question

If I run this javascript:

var a,b=Element.prototype;
for(a in b)b[a];

Firefox gives me this error:

TypeError: Value does no         


        

Answer 1

The Firefox (and recent IE) behavior here is because the property getters for some properties (say firstChild) are on the prototype object bu the properties make no sense on the prototype itself. Trying to get them on the prototype will throw.

This is the behavior required by the specification, in fact. See http://dev.w3.org/2006/webapi/WebIDL/#dfn-attribute-getter step 2 substep 2 subsubstep 2. Firefox and IE are following the spec here and WebKit-based browsers are not.