去除其中重复字符

<SCRIPT LANGUAGE="JavaScript">
<!--
var stra="a,b,c,d,e,f";
var strb="e,m,n,c,b,z,y";
//需要剔除b,c,e三个元素
var str=stra+","+strb;
var strArr=str.split(",");
//排序
strArr.sort();
var result=new Array();
var tempStr="";
for(var i in strArr)
{
     if(strArr[i] != tempStr)
     {
          result.push(strArr[i]);
          tempStr=strArr[i];
     }
     else
     {
          continue;
     }
}
alert(result.join(","))
//-->
</SCRIPT>