clone

function clone(obj){
var o;
switch(typeof obj){
case 'undefined': break;
case 'string' : o = obj + '';break;
case 'number' : o = obj - 0;break;
case 'boolean' : o = obj;break;
case 'object' :
if(obj === null){
o = null;
}else{
if(obj instanceof Array){
o = [];
for(var i = 0, len = obj.length; i < len; i++){
o.push(clone(obj[i]));
}
}else{
o = {};
for(var k in obj){
o[k] = clone(obj[k]);
}
}
}
break;
default:
o = obj;break;
}
return o;
}