webjs--hash数组去重

<script type="text/javascript">
function unique(arr){
var hash=[];
hash[arr[0]]=1;
for (var i=1;i<arr.length ;i++ )
{
if(hash[arr[i]]===undefined){
hash[arr[i]]=1
}
}

var keys=[],i=0;
for (keys[i++] in hash);
console.log(keys);

}

console.time('unique');
unique([20,50,20,40,50,10,20]);
console.timeEnd('unique');

</script>