到某个指定的页面不可以后退

<script type="text/javascript">
window.onload=function(){
if (window.history && window.history.pushState) {
window.onpopstate=function(){
window.history.pushState('forward', null, '#');
window.history.forward(1);
alert("请先完成注册,再进行其他操作！")
}
window.history.pushState('forward', null, '#');
window.history.forward(1);　
}
}　
</script>