<script> location.app="test"; var inter; function check(){ if(!location.app){ alert("location.app is empty:" + location.app); clearInterval(inter); } } alert("location.app:" + location.app); inter=setInterval("check()",5000); </script> when I use location object, I set a value "test" to it's attribute: location.app="test"; but after a while, it's cleared by firefox! and I get undefined when I use this attribute. firefox should keep the value of location.app instead of clearing it.

js_99, which exact Firefox version are you using? I suspect this is a duplicate of bug 988863, but wanted to double-check that you're using a version that bug was present in.

(In reply to Boris Zbarsky [:bz] (on PTO, reviews are slow) from comment #1) > js_99, which exact Firefox version are you using? I suspect this is a > duplicate of bug 988863, but wanted to double-check that you're using a > version that bug was present in. firefox 28.0

Thanks. I can reproduce that. What happens is that we install the WebIDL quickstub for window.location, so never even hit the resolve hook code for it. So nothing keeps the wrapper alive. Bug 988863 fixes that in Firefox 29, and we released that today, so I guess this is fixed now at least.