function unique(data){
data = data || [];
var a = {};
for (var i=0; i<data.length; i++) {
var v = data[i];
if (typeof(a[v]) == 'undefined'){
a[v] = 1;
}
};
data.length=0;
for (var i in a){
data[data.length] = i;
}
return data;
}

function test(){
var arr = [9,1,3,8,7,7,6,6,5,7,8,8,7,4,3,1];
var arr1 = unique(arr);
alert(arr1.join(","));
}
test();