Strings in javascript

gistfile1.js

var str = new String("foo");  // String Object 
typeof str;                   // return "Object"
typeof str.valueOf();         // return "String"

var str = String("foo");      // Primitive String
typeof str;                   // return "String"

var str = "foo";              // Primitive String (literal)
typeof str;                   // return "String"

var str = String(45);         // Primitive String also called String Function
typeof str;                   // return "String"
str;                          // return "45"