var extendDeep = function(parent,child){		var i,		toStr = Object.prototype.toString,		astr  = ‘[object Array]‘;	child = child || {};	for( i in parent){		if(parent.hasOwnProperty(i)){			if(typeof parent[i] === ‘object‘){				child[i] = toStr.call(parent[i])=== astr ? [] : {};				extendDeep(parent[i],child[i]);			}else{				child[i] = parent[i];			}					}	}		return child;};//测试代码：var obj1 = {	a : 1,	b : {		c : {			d : 1		}	}};var obj2 = extendDeep(obj1);console.log(obj2);