如果你使用的是带有hashbang (/#!/) url的JS框架，比如Angular，这可能会成为一个严重的问题。实际上，Angular会认为带有非hashbang片段的url是无效的，并抛出一个错误:

Error: Invalid url "http://example.com/#_=_", missing hash prefix "#!".

如果你在这种情况下(重定向到你的域根目录)，不要这样做:

window.location.hash = ''; // goes to /#, which is no better

简单地做:

window.location.hash = '!'; // goes to /#!, which allows Angular to take care of the rest

博士TL;

if (window.location.hash === "#_=_"){
    history.replaceState 
        ? history.replaceState(null, null, window.location.href.split("#")[0])
        : window.location.hash = "";
}

完整版本与一步一步的说明

// Test for the ugliness.
if (window.location.hash === "#_=_"){

    // Check if the browser supports history.replaceState.
    if (history.replaceState) {

        // Keep the exact URL up to the hash.
        var cleanHref = window.location.href.split("#")[0];

        // Replace the URL in the address bar without messing with the back button.
        history.replaceState(null, null, cleanHref);

    } else {

        // Well, you're on an old browser, we can get rid of the _=_ but not the #.
        window.location.hash = "";

    }

}

循序渐进:

We'll only get into the code block if the fragment is #_=_. Check if the browser supports the HTML5 window.replaceState method. Clean the URL by splitting on # and taking only the first part. Tell history to replace the current page state with the clean URL. This modifies the current history entry instead of creating a new one. What this means is the back and forward buttons will work just the way you want. ;-) If the browser does not support the awesome HTML 5 history methods then just clean up the URL as best you can by setting the hash to empty string. This is a poor fallback because it still leaves a trailing hash (example.com/#) and also it adds a history entry, so the back button will take you back to #_-_.

了解更多关于历史的知识。

了解window.location的更多信息。

这将删除附加字符到您的url

<script type="text/javascript">
 var idx=window.location.toString().indexOf("#_=_"); 
   if (idx > 0) { 
     window.location = window.location.toString().substring(0, idx); 
   } 
</script>

我使用这个，删除'#'符号。

<script type="text/javascript">
    if (window.location.hash && window.location.hash == '#_=_') {
        window.location.href = window.location.href.split('#_=_')[0];
    }
</script>

不知道他们为什么这样做，但是，你可以通过重置页面顶部的哈希来解决这个问题:

if (window.location.hash == "#_=_")
  window.location.hash = "";

我看不出这个问题与facebook AJAX有什么关系。事实上，禁用JavaScript和完全基于重定向的登录也会出现这个问题。

一个与facebook交换的例子:

1. GET <https://www.facebook.com/dialog/oauth?client_id=MY_APP_ID&scope=email&redirect_uri=MY_REDIRECT_URL> RESPONSE 302 Found Location: <https://www.facebook.com/connect/uiserver.php?[...]>  
2. GET <https://www.facebook.com/connect/uiserver.php?[...]> RESPONSE 302 Found MY_REDIRECT_URL?code=FB_CODE#_  
3. GET MY_REDIRECT_URL?code=FB_CODE#_  

我也只在火狐浏览器上遇到过这种情况。