Difference Between == and === : A Simple Comparison

Beginners in JavaScript may be confused with the two equal operators, === and ==. So what is the difference between them?

Consider the following example:

console.log( false == "" );
console.log( false === "" );
console.log( 5 == "5" );
console.log( 5 === "5" );

The first and third statements use the == operator so true is printed to the console. The other two statements give false as the results. So Why?

Actually the two operators behave almost the same. Just that the === operator prohibitstype conversion of operands. So the twooperands of the
=== operator need to be exactly the same (both the value and the type) to give a result of true.

Douglas Crockford gives the following advice in his famous book, JavaScript: The Good Parts: (and I agree with him)

The evil twins do the right thing when the operands are of the same type, but if they are of different
types, they attempt to coerce the values. the rules by which they do that are complicated and unmemorable. 

...

The lack of transitivity is alarming. My advice is to never use the evil twins. Instead, always
use 

===

and 

!==

.
All of the comparisons just shown produce 

false

 with
the 

===

 operator.