eg:给数组添加获取最大值的方法 ~~~ function max( ){ var i, max = this[0]; for (i = 1; i < this.length; i++) { if (max < this[i]) max = this[i]; } return max; } Array.prototype.max = max; var myArray = new Array(7, 1, 3, 11, 25, 9 ); document.write(myArray.max()); ~~~