function clone(obj){
var type = Object.prototype.toString.call(obj).slice(8,-1).toLowerCase();
if(type=='object'){
var json = {};
for(i in obj){
if(obj.hasOwnProperty(i)){
json[i] = clone(obj[i]);
}
}
return json;
}else if(type=='array'){
var arr = [];
for(var i=0; i<obj.length; i++){
arr[i] = clone(obj[i]);
}
return arr;
}else{
return obj;
}
}