Redirecting external URLs to an exit page

What would be the best way to redirect users who request an external URL, to a sort of good-bye page?

I know I could work hard to install some sort of mod_rewrite-like module. But can't I do some so开发者_如何转开发rt of Page_OnRequest type function in global.asax or the master pages?

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You could have these urls actually point to a redirection page on your own site before forwarding them on to the ultimate destination:

<a href="redirect.aspx?url=stackoverflow.com">Stack Overflow</a>

Then you could do whatever you wanted with the redirection, and it could be worked so that the redirection hid the url, encoded it, added parameters, etc.

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Easiest way is to use jQuery to hook the click event on all the tags on the page:

$(function(){

  $('a').click(function(e){
    var proceed       = true ;
    var anchor        = $(this) ;
    var href          = anchor.attr('href') ;
    var isExternalUrl = CheckForExternalUrl( href ) ;

    if ( isExternalUrl )
    {
      e.PreventDefault() ;
      window.location = "outside_link.aspx?url=" + href ;
      proceed         = false ;
    }
    return proceed ;
  }) ;
}) ;

Any link that gets clicked fires the event handler. External URLs will cause the page outside_link.aspx to loaded with the destination url in the query string. Internal URLs will behave normally.

Simple.