obj[n]与obj["n"]

<script>
			var obj={
				name:"孙悟空",
				age:18,
				gender:"男"
			}

//			console.log(obj.name);//孙悟空
//			console.log(obj[name]);//undefined
			console.log(obj["name"]);//孙悟空
</script>

　　

<script>
			var obj={
				name:"孙悟空",
				age:18,
				gender:"男"
			}
			for(var n in obj){
//				console.log(obj.n);//undefined
//				console.log(obj[n]);//不报错
				console.log(obj["n"]);//undefined
			}
</script>