var a   =   0;
var b   =   '';//empty string
if(a==b){
    console.log('equal');//this is printed in console
}else{
    console.log('not equal');
}

console.log(0 == '0');  // true
console.log(0 == '');   // true
console.log('' == '0'); // O'RLY?

console.log(false == undefined); // false
console.log(false == null);      // false
console.log(null == undefined);  // fal.... NO WAIT!

var a = 0;
var b = ''; //empty string
if(a == b){
    console.log('equal'); //this is printed in console
}else{
    console.log('not equal');
}

if(a === b){
    console.log('equal');
}else{
    console.log('not equal'); //this is printed in console
}