Performs a logical conjunction on two expressions.
If, and only if, both expressions evaluate to True, result is True. If either expression evaluates to False, result is False.
All objects are considered true.
Strings are considered false if, and only if, they are empty.
null and undefined are considered false.
Numbers are false if, and only if, they are zero.
Supported in the following document modes: Quirks, Internet Explorer 6 standards, Internet Explorer 7 standards, Internet Explorer 8 standards, Internet Explorer 9 standards. See Version Information.