``` <script type="text/javascript"> //自定義函數：刪除數組某一元素 Array.prototype.indexOf = function(val) { for (var i = 0; i < this.length; i++) { if (this[i] == val) return i; } return -1; }; Array.prototype.remove = function(val) { var index = this.indexOf(val); if (index > -1) { this.splice(index, 1); } }; var test = ['tom','jack','lucy']; test.remove('lucy');//刪除lucy </script> ```