1、变量，数据类型
<html>
<head>
<title>变量</title>
</head>
<body>
<h3>变量 数据类型</h3>
<script type="text/javascript">
var i = 10;
var k = 20;
var d = new Date();
document.write("i = " + i + "<br/>");
document.write("d = " + d + "<br/>");
i = new Object();
document.write("i = " + i + "<br/>");
i = new Array(10,20,30);
document.write("i = " + i + "<br/>");
j = k +20;
document.write("j = " + j + "<br/>");
var name = '张三';//字符串不区分",'
document.write("name = " + name + "<br/>");
var sex = '男';
document.write("sex = " + sex + "<br/>");
var married= false;
var test;
document.write("test = " + test + "<br/>");
test = null;
document.write("test = " + test + "<br/>");
var obj = new Object();
document.write("obj = " + obj + "<br/>");
</script>
<h3>2.检测变量的数据类型</h3>
<script type="text/javascript">
document.write("obj的类型 " + (typeof obj) + "<br/>");
document.write("test:" + (typeof obj) + "<br/>");
document.write("name 的类型" + (typeof name) +"<br/>");
document.write("sex 的类型" + (typeof sex) + "<br/>");
document.write("j :" + (typeof j) +"<br/>");
document.write("married " + (typeof married ) + "<br/>");
document.write("i 的类型 " + (typeof i) + "<br/>");
document.write("i:" , i instanceof Array,"<br/>");
document.write("i:", i instanceof Date,"<br/>");
</script>
<h3>3、运算符</h3>
<script type="text/javascript">
var a = 5;
var b = 3;
document.write("5 /3 = ",5/3,"<br/>");
document.write("8 / 2 = ",8/2,"<br/>");
</script>
</body>
</html>
结果：
