(function(){
    String.prototype.startsWith = String.prototype.startsWith || function (str) {
    var reg = new RegExp("^" + str);
    return reg.test(this);
    }
    String.prototype.endsWith = String.prototype.endsWith || function (str) {
        var reg = new RegExp(str + "$");
        return reg.test(this);
    }
}())