Double equals (==) is abstract equality comparison operator, which transforms the operands to the same type before making the comparison.
For example,
4 == 4 // true '4' == 4 // true 4 == '4' // true 0 == false // true
Triple equals (===) are strict equality comparison operator, which returns false for different types and different content.
For example,
4 === 4 // true
4 === '4' // false
var v1 = {'value': 'key'};
var v2 = {'value': 'key'};
v1 === v2 //false