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问题:

I am trying to create my own website access library (for fun) like Google Analytics where I can detect when a user accesses my website, what pages they view etc.

Is there a way to determine when the user leaves a page &/or leaves the website for good?

I have successfully coded (in python) the detecting when the user 1st accesses my site (using a cookie) & how to determine what pages they view. But I don't know how I could detect when they user leaves the website for good?

Is there a way in javascript (maybe I can detect when the page/url is changing?). I know in HTTP there is a referrer header that tells me where the user came from, maybe when the user moves to another website (outside of mine), I can be notified of this (because I will be the referrer in that HTTP request)? Am I correct?

回答1:

Using jquery you can trigger this:

$(window).bind('beforeunload', function() {
    // ajax call perhaps
    // triggering a write to db or filesystem...
});

Pure javascript way:

<html>
<head>
<script>
function closeIt()
{
  return "Any string value here forces a dialog box to \n" + 
         "appear before closing the window.";
}
window.onbeforeunload = closeIt;
</script>
</head>
<body>
  <a href="http://www.somewhere.com">Click here to navigate to 
      www.somewhere.com</a>
</body>
</html>

回答2:

As long the user plays by the rules you expect the onbeforeunload will work. That means, closing a tab, or closing the window, or navigating to another site.
However, you have no way to detect this reliably with javascript, onbeforeunload doens't fire in many cases, such as shutting down the browser (ctrl+q), browser crash, history (back) and opera and some versions of chrome have limited support to onbeforeunload.

If you want to detect it with high precision, you must send Ajax requests periodically that shows the user is "still alive". register those requests in a database or file and analyze it by the time sequence.
So, if you "ping" the database every 20 seconds you can know from pretty simple queries that the browser hasn't "pinged" after a short while, and determine the user is no longer in the site.

回答3:

You can mark all links on your site as inner or outer links. They must point to your site, but then redirect to location, selected by user. Before redirection you can point that user left away from your site.

But.

I'd better putted on every page on your site a little script which (say every 20-30 sec) make a GET request to specific url on your site. So you can track number of each user requests.

回答4:

There is an unload event you can handle in JavaScript. For example:

window.onunload = unloadPage;

function unloadPage()
{
 alert("unload event detected!");
}

Unfortunately, there is no way to tell where the user is actually going when they leave the current page (unlike a referrer, when you enter the page).

One idea is, to set a variable (perhaps in database) in the unload handler (via AJAX call or what not), and then remove it if user enters another page shortly after that. Whichever record is not removed (or deactivated - soft deletes) is your last exit event before the user actually bounced off your web site or closed the browser.