1. <body>|
    2.     <script>
    3.         var arr=["a@b.com","c@d.com","a@b.com"]
    4.         arr.forEach(item => {
    5.             var count=0
    6.             for(i=0;i<arr.length;i++){
    7.                 if(arr[i]==item){
    8.                     count++
    9.                 }
    10.             }
    11.             if(count==2){
    12.                 console.log("邮箱重复："+item)
    13.             }
    14.         });
    16.     </script>
    17. </body>