Thanks for taking the time to contribute to the jQuery project! Please provide a reduced test case on http://jsFiddle.net that reproduces the issue experienced to help us assess your ticket!

Additionally, test against the jQuery (edge) version to ensure the issue still exists.

Why would you pass .attr() a number and not a string?

Agreed with miketaylr, however:

Tested with jQuery (edge) here http://jsfiddle.net/ez57B/3/ across Chrome latest, Firefox 4, Opera, IE6 and IE8. All of these browsers had no problem at all setting the checked value using a number rather than a string with no exception experienced.

Please ideally use the string version instead regardless as we haven't documented a number functioning correctly for 'checked' values.

I don't know what is edge, I'm using 1.6.1 uncompressed and the error is in line 2196 : "value.toLowerCase is not a function". prop() is working fine with this. Also documentation says nothing about expected argument type. Some users are using 1/0 as boolean states, and it works with object properties like checked, so maybe you should handle this properly.

I've found this commit https://github.com/jquery/jquery/commit/cf702496ee28830f3488ed3f1c3940cfbb2dfa8f which probably fixed this.

It may work now, but your call does not make sense. You can do .attr("checked", "checked"), .attr("checked", true), .prop("checked", true), or simply elem.checked = true. No numbers should be involved here.

Right, but elem.checked = 1 works too, isn't it? No matter, it's fixed now.