history.length计算
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>History对象</title>
</head>
<script type="text/javascript">
var HL = window.history.length ;
document.write(HL);
</script>
<body>
</body>
</html>
为什么我修改一次length,就是把代码length删掉再写,右边的结果框每次都加三？？？到底是怎么计算历史记录的？？求指教
