你也可以在Facebook回调的redirect_uri参数上指定你自己的散列，这在某些情况下可能是有帮助的，例如/api/account/callback#home。当你被重定向回来，它至少是一个哈希，对应于一个已知的路由，如果你使用backbone.js或类似的(不确定jquery移动)。

这是Facebook出于安全考虑而设计的。下面是Facebook团队成员埃里克·奥斯古德的解释:

This has been marked as 'by design' because it prevents a potential security vulnerability. Some browsers will append the hash fragment from a URL to the end of a new URL to which they have been redirected (if that new URL does not itself have a hash fragment). For example if example1.com returns a redirect to example2.com, then a browser going to example1.com#abc will go to example2.com#abc, and the hash fragment content from example1.com would be accessible to a script on example2.com. Since it is possible to have one auth flow redirect to another, it would be possible to have sensitive auth data from one app accessible to another. This is mitigated by appending a new hash fragment to the redirect URL to prevent this browser behavior. If the aesthetics, or client-side behavior, of the resulting URL are of concern, it would be possible to use window.location.hash (or even a server-side redirect of your own) to remove the offending characters.

来源:https://developers.facebook.com/bugs/318390728250352/

使用angular和angular ui router，你可以修复这个问题

    app.config(function ($stateProvider, $urlRouterProvider, $locationProvider) {

      // Make a trailing slash optional for all routes
      // - Note: You'll need to specify all urls with a trailing slash if you use this method.
      $urlRouterProvider.rule(function ($injector, $location) {
        /***
        Angular misbehaves when the URL contains a "#_=_" hash.

        From Facebook:
          Change in Session Redirect Behavior
          This week, we started adding a fragment #_=_ to the redirect_uri when this field is left blank.
          Please ensure that your app can handle this behavior.

        Fix:
          http://stackoverflow.com/questions/7131909/facebook-callback-appends-to-return-url#answer-7297873
        ***/
        if ($location.hash() === '_=_'){
          $location.hash(null);
        }

        var path = $location.url();

        // check to see if the path already has a slash where it should be
        if (path[path.length - 1] === '/' || path.indexOf('/?') > -1) {
          return;
        }
        else if (path.indexOf('?') > -1) {
          $location.replace().path(path.replace('?', '/?'));
        }
        else {
          $location.replace().path(path + '/');
        }
      });

      // etc ...
    });
});

对于那些正在寻找简单答案的人 加上这个，对我很管用

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

请查看Paul Schwarz的完整回答

https://stackoverflow.com/a/18305085/2694806

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>

如果你使用vue-router，你可以添加到路由列表:

{
  path: '/_=_',
  redirect: '/', // <-- or other default route
},