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
<script>
window.location.hash = "no-back-button";
// Again because Google Chrome doesn't insert
// the first hash into the history
window.location.hash = "Again-No-back-button";
window.onhashchange = function(){
window.location.hash = "no-back-button";
}
</script>
其他回答
This code will disable the back button for modern browsers which support the HTML5 History API. Under normal circumstances, pushing the back button goes back one step, to the previous page. If you use history.pushState(), you start adding extra sub-steps to the current page. The way it works is, if you were to use history.pushState() three times, then start pushing the back button, the first three times it would navigate back in these sub-steps, and then the fourth time it would go back to the previous page.
如果您将此行为与popstate事件上的事件侦听器结合在一起，您实际上可以建立一个无限循环的子状态。因此，您加载页面，按下一个子状态，然后点击返回按钮，弹出一个子状态，并按下另一个子状态，因此，如果您再次按下返回按钮，它将永远不会没有子状态可按。如果你觉得有必要禁用后退按钮，这将使你达到目的。
history.pushState(null, null, 'no-back-button');
window.addEventListener('popstate', function(event) {
history.pushState(null, null, 'no-back-button');
});
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.
反应
对于React项目中的模态组件，打开或关闭模态，控制浏览器返回是一个必要的动作。
The stopBrowserBack: the stop of the browser back button functionality, also get a callback function. This callback function is what you want to do: const stopBrowserBack = callback => { window.history.pushState(null, "", window.location.href); window.onpopstate = () => { window.history.pushState(null, "", window.location.href); callback(); }; }; The startBrowserBack: the revival of the browser back button functionality: const startBrowserBack = () => { window.onpopstate = undefined; window.history.back(); };
在项目中的使用:
handleOpenModal = () =>
this.setState(
{ modalOpen: true },
() => stopBrowserBack(this.handleCloseModal)
);
handleCloseModal = () =>
this.setState(
{ modalOpen: false },
startBrowserBack
);
你可以放一个小脚本，然后检查。它将不允许您访问前一页。
这是用JavaScript完成的。
<script type="text/javascript">
function preventbackbutton() { window.history.forward(); }
setTimeout("preventbackbutton()", 0);
window.onunload = function () { null };
</script>
窗外。Onunload函数当您试图通过浏览器访问返回或上一页时触发。
<html>
<head>
<title>Disable Back Button in Browser - Online Demo</title>
<style type="text/css">
body, input {
font-family: Calibri, Arial;
}
</style>
<script type="text/javascript">
window.history.forward();
function noBack() {
window.history.forward();
}
</script>
</head>
<body onload="noBack();" onpageshow="if (event.persisted) noBack();" onunload="">
<H2>Demo</H2>
<p>This page contains the code to avoid Back button.</p>
<p>Click here to Goto <a href="noback.html">NoBack Page</a></p>
</body>
</html>
