JavaScript克隆对象的三个实用方法

function clone(obj){
	var o;
	if(typeof obj == "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]);
				}
			}
		}
	}else{
		o = obj;
	}
	return o;
}
function clone(obj){
	var o;
	if(typ