js arr unique

arrunique : function(array) {
var ret = [], done = {};
try {
for (var i = 0, length = array.length; i < length; i++) {
var tmp = array[i];
if (!done[tmp]) {
done[tmp] = true;
ret.push(tmp);
}
}
} catch (e) {
ret = array;
}
return ret;
}

}