[jQuery] Can't Add a checked=checked Attribute to Input tag

[Joe]

Very simply, I want this function to attach the attribute
checked=checked to the input with the id=ext[agree]Y.

The following code does not do this and I'm not sure why...


$("ext\\[agree\\]Y").attr("checked", "checked");



Any help or ideas is greatly appreciated.  Other ways of doing this
would be great as well.  I just want to add this upon form submission.

Thanks.