The difference between == and === is that: 1. == converts the variable values to the same type before performing comparison. This is called type coercion. 2. === does not do any type conversion (coercion) and returns true only if both values and types are identical for the two variables being compared. Example: var one = 1 ; var one_again = 1 ; var one_string = "1" ; // note: this is string console . log ( one == one_again ); // true console . log ( one === one_again ); // true console . log ( one == one_string ); // true. See below for explanation. console . log ( one === one_string ); // false. See below for explanation