$(document).ready(function() {

    var arr1=["dog","dog","fish","cat","cat","fish","apple","orange"]

    var arr2=["cat","fish","mango","apple"]

    var uniquevalue=[];
    var seconduniquevalue=[];
    var finalarray=[];

    $.each(arr1,function(key,value){

       if($.inArray (value,uniquevalue) === -1)
       {
           uniquevalue.push(value)

       }

    });

     $.each(arr2,function(key,value){

       if($.inArray (value,seconduniquevalue) === -1)
       {
           seconduniquevalue.push(value)

       }

    });

    $.each(uniquevalue,function(ikey,ivalue){

        $.each(seconduniquevalue,function(ukey,uvalue){

            if( ivalue == uvalue)

            {
                finalarray.push(ivalue);
            }   

        });

    });
    alert(finalarray);
});

在ECMAScript 6（又名ECMAScript2015）中，Set可用于过滤重复项。然后可以使用扩展运算符将其转换回数组。

var names = ["Mike","Matt","Nancy","Adam","Jenny","Nancy","Carl"],
    unique = [...new Set(names)];

var uniqueCompnies = function(companyArray) {
    var arrayUniqueCompnies = [],
        found, x, y;

    for (x = 0; x < companyArray.length; x++) {
        found = undefined;
        for (y = 0; y < arrayUniqueCompnies.length; y++) {
            if (companyArray[x] === arrayUniqueCompnies[y]) {
                found = true;
                break;
            }
        }

        if ( ! found) {
            arrayUniqueCompnies.push(companyArray[x]);
        }
    }

    return arrayUniqueCompnies;
}

var arr = [
    "Adobe Systems Incorporated",
    "IBX",
    "IBX",
    "BlackRock, Inc.",
    "BlackRock, Inc.",
];

这可能是从阵列中永久删除重复项的最快方法之一比这里的大多数功能快10倍。&狩猎速度快78倍

function toUnique(a,b,c){               //array,placeholder,placeholder
 b=a.length;while(c=--b)while(c--)a[b]!==a[c]||a.splice(c,1)
}

测试：http://jsperf.com/wgu演示：http://jsfiddle.net/46S7g/更多信息：https://stackoverflow.com/a/25082874/2450730

如果你看不懂上面的代码，请看一本javascript书，或者这里有一些关于较短代码的解释。https://stackoverflow.com/a/21353032/2450730

var duplicates = function(arr){
     var sorted = arr.sort();
   var dup = [];
   for(var i=0; i<sorted.length; i++){
        var rest  = sorted.slice(i+1); //slice the rest of array
       if(rest.indexOf(sorted[i]) > -1){//do indexOf
            if(dup.indexOf(sorted[i]) == -1)    
         dup.push(sorted[i]);//store it in another arr
      }
   }
   console.log(dup);
}

duplicates(["Mike","Matt","Nancy","Adam","Jenny","Nancy","Carl"]);

解决方案1

Array.prototype.unique = function() {
    var a = [];
    for (i = 0; i < this.length; i++) {
        var current = this[i];
        if (a.indexOf(current) < 0) a.push(current);
    }
    return a;
}

解决方案2（使用集合）

Array.prototype.unique = function() {
    return Array.from(new Set(this));
}

Test

var x=[1,2,3,3,2,1];
x.unique() //[1,2,3]

表演

当我在chrome中测试两种实现（有和没有Set）的性能时，我发现有Set的实现要快得多！

Array.prototype.unique1=函数（）{变量a=[]；对于（i=0；i<this.length；i++）{无功电流=此[i]；如果（a.indexOf（current）<0）a.push（current）；}返回a；}Array.prototype.unique2=函数（）{return Array.from（new Set（this））；}var x=[]；对于（var i=0；i<10000；i++）{x.push（“x”+i）；x.push（“x”+（i+1））；}console.time（“unique1”）；console.log（x.unique1（））；console.timeEnd（“unique1”）；console.time（“unique2”）；console.log（x.unique2（））；console.timeEnd（“unique2”）；