Casting type to string : Type Conversion « Number Data Type « JavaScript Tutorial

1. JavaScript Tutorial
2. Number Data Type
3. Type Conversion

When casting type to string, JavaScript simply calls the toString() method.

The type cast can produce a string for a null or undefined value without error.

var s1 = String(null);    //"null"
var oNull = null;
var s2 = oNull.toString(); //won't work, causes an error