以前项目中用到自己写的，应该没有bug吧，有更好的也欢迎大家指教， var Return_AddStrFn=function (oldArr, newArr) {         var t = this; 　　　　　　　//去重复的方法         Array.prototype.unique4 = function () {             // this = arr;             var temp = new Array();             this.sort();             for (i = 0; i < this.length; i++) {                 if (this[i] == this[i + 1]) {                     continue;                 }                 temp[temp.length] = this[i];             }             return temp;         }         var a = d = oldArr.unique4(); //旧数组         var b = e = newArr.unique4();//新数组         var c = [];         var dels = [];         function f() {             a.sort();             b.sort();             var i = 0;             var j = 0;             while (i < a.length && j < b.length) {                 if (a[i] < b[j]) {                     c.push(a[i]);                     i++;                 } else if (b[j] < a[i]) {                     c.push(b[j]);                     j++;                 } else {                     i++;                     j++;                 }             }             while (i < a.length) {                 c.push(a[i]);                 i++;             }             while (j < b.length) {                 c.push(b[j]);                 j++;             }         }         f();         //alert("c:" + c);         //alert("d:" + d);         var addstr = [];         for (var i = 0; i < c.length; i++) {             for (var j = 0; j < e.length; j++) {                 if (e[j] == c[i]) {                     addstr.push(e[j]);                 }             }         }         return addstr; //新增的         //for (var i = 0; i < c.length; i++) {         //    for (var j = 0; j < d.length; j++) {         //        if (d[j] == c[i]) {         //            dels.push(d[j]);         //        }         //    }         //}         //alert("dels:" + dels); //删除的     }