
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>演示JS中的运算</title>
</head>
<body>
<script type="text/javascript">
var num = "21";
num = num + 5;
alert(num)
var t = "x";
t = t - 1;
alert(t)
var x = 3;
x = x++;
alert(x);
</script>
</body>
</html>



