<script>
var arr = [
{id:1,city:"水果",parent_id:0},
{id:2,city:"蔬菜",parent_id:0},
{id:3,city:"苹果",parent_id:1},
{id:4,city:"香菜",parent_id:2},
];
var treeArr = [];
function tree( arr , pid , level){
for (var i = 0; i < arr.length; i++) {
if( arr[i].parent_id == pid ){
arr[i].level = level;
treeArr.push(arr[i]);
tree( arr,arr[i].id,level+1 );
}
}
}
tree( arr , 0 , 0);
for (var i = 0; i < treeArr.length; i++) {
var tmpStr = "";
for (var j = 0; j < treeArr[i].level; j++) {
tmpStr += "--";
}
document.write( tmpStr + treeArr[i].city + "<br/>");
}
</script>
js无限极分类
原文：http://blog.51cto.com/boysmusic/2046719
