javascript conditional evaluation code example

Example: javascript conditional evaluation

if ( expression )
Here are some expressions and their result
	Undefined: false
	Null: false
	Boolean: the result equals the input argument (no conversion)
	Number: false if the argument is +0, -0, or NaN; otherwise true
	String: false if the argument is an empty string (length = 0); 
			otherwise true
	Object: true