var arr=["a","b","c","d","c","b","d","f"];
var newarr=[];//存放不重复元素的数组
var count=[];//记录重复元素的元素和索引值
for(var i=0;i<arr.length;i++)
{
    var type=true;
    for(var j=0;j<newarr.length;j++)
    {
        if(newarr[j]==arr[i]){
         type=false;
            var typeC=true;
            for(var k=0;k<count.length;k++)
            {
                if(count[k][0]==arr[i])
                {
                    count[k][1]++;
                    typeC=false;
                    break;
                }
            }
            if(typeC){
                count.push([arr[i],1]);
            }
            document.write(arr[i]+" "+i+"<br>");
            break;
        }
    }
    if(type)
    {
        newarr.push(arr[i]);
    }
}
document.write(newarr+"<br>");
document.write(count);