closed → reopened
Because we hooked up jQuery.attr to attribute retrieval in Sizzle and because we currently have the value attrHook in place to always retrieve the value property rather than the content attribute for back-compat reasons AND because Sizzle tries querySelectorAll first, IE6/7 selects with the value property and other browsers select with the attribute (because querySelectorAll follows spec and uses the attribute). This is an inconsistency for all inputs, but will not be fixed until we have deprecated and removed the value attrHook.
I'll reopen so we can keep track of possible value attrHook deprecation. .prop or .val should be used to retrieve the value property anyway.