如何判断一个窗口是否存在于 Javascript 中？
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How to tell if a window exists in Javascript?
提问by Andrew
I've seen ways of seeing if a window a particular script opened is still opened, but what if it didn't?
我已经看到了查看特定脚本打开的窗口是否仍然打开的方法，但如果没有呢？
I have a small window that has a button to click to load the large window. When I close the large one, I want a particular onUnloador onBeforeUnloadto fire iff the small one is closed; if it's still open, those procedures will not fire. I may be having simply a massive brain fart but I can't figure out how to check if the other window is open. The big one isn't opening it, so I can't simply record the handle from opening it.
我有一个小窗口，上面有一个按钮可以点击加载大窗口。当我关闭大的时，我想要一个特定的onUnload或onBeforeUnload当小一个关闭时触发；如果它仍然打开，这些程序将不会触发。我可能只是有一个巨大的脑放屁，但我不知道如何检查另一个窗口是否打开。大的没有打开它，所以我不能简单地记录打开它的手柄。
In shorter terms: If window A opened window B, how can I check within window B if window A still exists?
简而言之：如果窗口 A 打开了窗口 B，我如何在窗口 B 中检查窗口 A 是否仍然存在？
回答by chaos
if(window.opener && !window.opener.closed)
alert('Yup, still there.');
回答by Juan Mendes
window.closedwill be set to true if you popped a window and it was closed (by script or user).
window.closed如果您弹出一个窗口并且它已关闭（由脚本或用户），则将设置为 true。
var win = window.open('...')';
if (win.closed)
Your case seems to be the following:
你的情况似乎如下：
From a popup window, you can check if the window that opened it is still open using window.opener.closed
从弹出窗口中，您可以检查打开它的窗口是否仍然打开使用 window.opener.closed
Get handle to a window by name
按名称获取窗口句柄
I mentioned there's no way to just get the window handle by name in the comments. However, I did some research and found that the following works in FF/IE/Chrome; it's a hack, I didn't see it mentioned anywhere as the expected behavior, so I wouldn't rely on it too much, but it was fun to find it works! In my code, I would still just make sure to pass around the required handles.
我提到没有办法在评论中按名称获取窗口句柄。但是，我做了一些研究，发现以下在 FF/IE/Chrome 中有效；这是一个 hack，我没有看到任何地方提到它作为预期的行为，所以我不会太依赖它，但发现它有效很有趣！在我的代码中，我仍然会确保传递所需的句柄。
//opened a window without storing a handle, but gave it a name
window.open('/some/url', 'xxx');
// now I need to get a reference to that window
// Calling open without setting a url gets you
// a reference and doesn't reload the window
var win = window.open('', 'xxx')
回答by Audrius
Use try{} and catch(err){}.
使用 try{} 和 catch(err){}。
try{
window.opener.document.body.getElementById('#elementId'); // do some action with window. opener
}
catch(err){
// if we are here then probably there is no window.opener
window.close(); // closing this window or whatever you want
}
回答by Ritwik
Try the following code:
试试下面的代码：
if (!!window) {
console.log('Exist');
}
