<!-- 第一种: -->
<script type="text/javascript">
window.location.href = "login.jsp?backurl=" + window.location.href;
</script>
<!-- 第二种: -->
<script type="text/javascript">
alert("返回"); window.history.back(-1);
</script>
<!-- 第三种:-->
<script type="text/javascript">
window.navigate("top.jsp");
</script>
<!-- 第四种: -->
<script type="text/javascript">
self.location = 'top.htm';
</script>
<!-- 第五种: -->
<script type="text/javascript">
alert("非法访问!"); top.location = 'xx.jsp';
</script>