Javascript String startsWith(s)

String.prototype.startsWith = function (s) {
    if (this.substr(0, s.length) === s)
        return true;
    else/*from   ww w  .  j av a  2 s  .  co m*/
        return false;
}

/**//from   www.j a  va 2  s . co m
 * Test is a string starts with another 
 * 
 * @param {String} s string to test with
 * @type boolean
 */
String.prototype.startsWith = function (s) {
 return (this.indexOf(s) === 0);
}