参考链接：http://blog.csdn.net/zhihua_w/article/details/52184289
以下方法自己都已经进行简单测试并且通过，需要的朋友可以直接拷贝使用！🙂
一、获取数组中相同元素的下标
/**
* @param needle 重复元素值
* @param elementArray 对应的元素数组
* @returns {Array} 返回一个数组
*/
var testArr = ["1","6","3","2","4","1","3","2","3","4","5"];
function searchKeys(needle, elementArray)
{
console.log("needle=>"+needle,"elementArray=>"+elementArray)
var result = [];
for (i in elementArray)
{
if (elementArray[i] == needle)
{
result.push(i);
}
}
return result;
}
console.log(searchKeys("1",testArr));
二、将数组中重复元素过滤掉重新返回一个新的数组
1、方法一：
var testArr = ["1","6","3","2","4","1","3","2","3","4","5"];
Array.prototype.method1 = function(){
var arr = []; //定义一个临时数组
for(var i = 0; i < this.length; i++){ //循环遍历当前数组
//判断当前数组下标为i的元素是否已经保存到临时数组
//如果已保存，则跳过，否则将此元素保存到临时数组中
if(arr.indexOf(this[i]) == -1){
arr.push(this[i]);
}
}
return arr;
}
document.write(testArr.method1())//这个调用方法，将结果显示出来
2、方法二：
var testArr = ["1","6","3","2","4","1","3","2","3","4","5"];
Array.prototype.method2 = function(){
var h = {}; //定义一个hash表
var arr = []; //定义一个临时数组
for(var i = 0; i < this.length; i++){ //循环遍历当前数组
//对元素进行判断，看是否已经存在表中，如果存在则跳过，否则存入临时数组
if(!h[this[i]]){
//存入hash表
h[this[i]] = true;
//把当前数组元素存入到临时数组中
arr.push(this[i]);
}
}
return arr;
}
document.write(testArr.method2())
3、方法三：
var testArr = ["1","6","3","2","4","1","3","2","3","4","5"];
Array.prototype.method3 = function(){
//直接定义结果数组
var arr = [this[0]];
for(var i = 1; i < this.length; i++){ //从数组第二项开始循环遍历此数组
//对元素进行判断：
//如果数组当前元素在此数组中第一次出现的位置不是i
//那么我们可以判断第i项元素是重复的，否则直接存入结果数组
if(this.indexOf(this[i]) == i){
arr.push(this[i]);
}
}
return arr;
}
document.write(testArr.method3())
3、方法四：将结果按照从小到大的顺序排列出来
var testArr = ["1","6","3","2","4","1","3","2","3","4","5"];
Array.prototype.method4 = function() {
//将数组进行排序
this.sort();
//定义结果数组
var arr = [this[0]];
for (var i = 1; i < this.length; i++) { //从数组第二项开始循环遍历数组
//判断相邻两个元素是否相等，如果相等说明数据重复，否则将元素写入结果数组
if (this[i] !== arr[arr.length - 1]) {
arr.push(this[i]);
}
}
return arr;
}
document.write(testArr.method4());
