I find the following codes throw an error in Firefox 20.0.1:

jQuery("body").attr("watch");

jQuery("body").attr("unwatch");

TypeError: name is not a function

Sizzle.attr()jquery-2.0.0.js (line 1600)

.attr()jquery-2.0.0.js (line 4071)

.access()jquery-2.0.0.js (line 790)

.attr()jquery-2.0.0.js (line 3751)

[Break On This Error]

val = fn && fn( elem, name, !documentIsHTML );

jquery-2.0.0.js (line 1600)