数组去重，获得数组中重复项。。。

var imgArr=[1,2,1,2,3,4,3];
 //var s = imgArr.join(",") +",";
  var arr = {};   
   for(var i = 0; i < imgArr.length; i++){ 
          arr[ imgArr[i]] = "";
     }
    var newImg = [];
  for(a in arr){
          newImg.push(a);   
   }
 console.log(newImg);

 

var imgArr=[1,2,1,2,3,4,3];

    //var s = imgArr.join(",") +",";
   var arr = {};   
   for(var i = 0; i < imgArr.length; i++)
      { arr[ imgArr[i]] = "";
                
       if(s.replace(imgArr[i] + ",", "").indexOf(imgArr[i] +",") > -1)
            {
          console.log("重复内容：" + imgArr[i]);
                      
        }
   }

  var newImg = [];
     for(a in arr){
           newImg.push(a);   
     }
  console.log(newImg);