var x = 13;
var y = 5
if (x != y) // true
document.write("1. x != y" + "<br />");
if (x !== y) // true
document.write("2. x !== y" + "<br />");
x = 13;
y = "5";
if (x != y) // true
document.write("3. x != y" + "<br />");
if (x !== y) // true
document.write("4. x !== y" + "<br />");
x = 13;
y = "13";
if (x != y) // false
document.write("5. x != y" + "<br />");
if (x !== y) // true // not equal type
document.write("6. x !== y" + "<br />");
/*
run:
1. x != y
2. x !== y
3. x != y
4. x !== y
6. x !== y
*/