for/in循环

1. for/in

遍历对象属性成员。

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>TestJS</title>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
</head>
<script type = "text/javascript">
	function init() {		
		var o = {x:1,y:2,z:3};
		for(var s in o){ console.log(s);}
	}
	</script>
<body onload=init()>
sam
</body>
</html>

 输出

x

TestJS.html (line 10)

y

TestJS.html (line 10)

z

TestJS.html (line 10)

 

遍历属性的值

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>TestJS</title>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
</head>
<script type = "text/javascript">
	function init() {		
		var o = {x:1,y:2,z:3};
		for(var s in o){ console.log(o[s]);}
	}
	</script>
<body onload=init()>
sam
</body>
</html>

 输出

1

TestJS.html (line 10)

2

TestJS.html (line 10)

3

TestJS.html (line 10)

 

遍历数组的值, 索引等于数组的属性

 

for(i in a) console.log(a[i]);