Performs a logical conjunction on two expressions.
If expression1 evaluates to false, result is expression1. Otherwise, result is expression2. Consequently, the operation returns true if both operands are true; otherwise, it returns false.
All objects are considered to be true.
Strings are considered to be false if they are empty.
null and undefined are considered to be false.
A Number is false if it is zero.
Supported in the following document modes: Quirks, Internet Explorer 6 standards, Internet Explorer 7 standards, Internet Explorer 8 standards, Internet Explorer 9 standards, Internet Explorer 10 standards, Internet Explorer 11 standards. Also supported in Store apps (Windows 8 and Windows Phone 8.1). See Version Information.