我正在用PHP做一个在线测试应用程序。我想限制用户在考试中返回。

我尝试了下面的脚本,但它停止了我的计时器。

我该怎么办?

定时器存储在cdtimer.js文件中。

<script type="text/javascript">
    window.history.forward();
    function noBack()
    {
        window.history.forward();
    }
</script>

<body onLoad="noBack();" onpageshow="if (event.persisted) noBack();" onUnload="">

我有一个考试计时器,它从一个MySQL值中获取考试的持续时间。计时器随之启动,但当我输入禁用后退按钮的代码时,它就停止了。我有什么问题?


当前回答

如何阻止反向功能:

历史。pushState(null, null, location.href); 窗口。Onpopstate = function () { history.go (1); };

其他回答

我遇到了这个问题,需要一个在各种浏览器上正确工作的解决方案,包括Mobile Safari(在发布时是iOS 9)。没有一个解决方案是完全正确的。我提供以下建议(在Internet Explorer 11、Firefox、Chrome和Safari上进行了测试):

history.pushState(null, document.title, location.href);
window.addEventListener('popstate', function (event)
{
  history.pushState(null, document.title, location.href);
});

注意事项:

history.forward() (my old solution) does not work on Mobile Safari --- it seems to do nothing (i.e., the user can still go back). history.pushState() does work on all of them. the third argument to history.pushState() is a url. Solutions which pass a string like 'no-back-button' or 'pagename' seem to work OK, until you then try a Refresh/Reload on the page, at which point a "Page not found" error is generated when the browser tries to locate a page with that as its URL. (The browser is also likely to include that string in the address bar when on the page, which is ugly.) location.href should be used for the URL. the second argument to history.pushState() is a title. Looking around the web most places say it is "not used", and all the solutions here pass null for that. However, in Mobile Safari at least, that puts the page's URL into the history dropdown the user can access. But when it adds an entry for a page visit normally, it puts in its title, which is preferable. So passing document.title for that results in the same behaviour.

经历了大多数现有的答案,没有解决方案,工作在chrome。

这个想法是让浏览器在会话历史中向前移动一页,有效地防止使用后退浏览器按钮离开该页。通过调用History.forward()方法,在页面中放置下面的行,可以做到这一点。

window.history.forward();

我在mdn web docs找到了这个解决方案,它在chrome中工作。

我觉得jordanhollinger.com上的这篇文章是最好的选择。与Razor的答案相似,但更清楚一些。下面的代码;全部归功于Jordan Hollinger:

页面:

<a href="/page-of-no-return.htm#no-back>You can't go back from the next page</a>

no return的JavaScript页面:

// It works without the History API, but will clutter up the history
var history_api = typeof history.pushState !== 'undefined'

// The previous page asks that it not be returned to
if ( location.hash == '#no-back' ) {
  // Push "#no-back" onto the history, making it the most recent "page"
  if ( history_api ) history.pushState(null, '', '#stay')
  else location.hash = '#stay'

  // When the back button is pressed, it will harmlessly change the url
  // hash from "#stay" to "#no-back", which triggers this function
  window.onhashchange = function() {
    // User tried to go back; warn user, rinse and repeat
    if ( location.hash == '#no-back' ) {
      alert("You shall not pass!")
      if ( history_api ) history.pushState(null, '', '#stay')
      else location.hash = '#stay'
    }
  }
}

这里的一些解决方案不会阻止回退事件的发生——它们让回退事件发生(浏览器内存中关于页面的数据丢失),然后它们播放一个向前事件,试图隐藏回退事件刚刚发生的事实。如果页面处于暂时状态,则该方法将不成功。

我为React写了这个解决方案(当React路由器不被使用时),它是基于vrfvr的答案。

它将真正阻止后退按钮做任何事情,除非用户确认弹出:

  const onHashChange = useCallback(() => {
    const confirm = window.confirm(
      'Warning - going back will cause you to loose unsaved data. Really go back?',
    );
    window.removeEventListener('hashchange', onHashChange);
    if (confirm) {
      setTimeout(() => {
        window.history.go(-1);
      }, 1);
    } else {
      window.location.hash = 'no-back';
      setTimeout(() => {
        window.addEventListener('hashchange', onHashChange);
      }, 1);
    }
  }, []);

  useEffect(() => {
    window.location.hash = 'no-back';
    setTimeout(() => {
      window.addEventListener('hashchange', onHashChange);
    }, 1);
    return () => {
      window.removeEventListener('hashchange', onHashChange);
    };
  }, []);

试试这个: 假设有两个页面Page1和Page2, Page1重定向到Page2

为了防止用户使用返回按钮访问Page1,您需要将上面的脚本放在Page1中

$(document).ready(async function (){
    history.pushState(null, null, location.href);
    window.onpopstate = function () {
        history.go(1);
    };
})