How to Create a Back Button That Works

< Webhelp

Using Server Side Includes

Alright, I'm tired of seeing all the JavaScript back buttons that sometimes work. If your server is capable (requires XSSI) it will work all the time regardless of the browser. An alternative could be cobbled together with CGI if your server doesn't support Extended SSI. (Or hollar at your host till they upgrade.)

Essentially you need to examine the HTTP_REFERER before creating a link with it.

<!--#if expr="${HTTP_REFERER} =/http/" -->
<A HREF="<!--#echo var="HTTP_REFERER" -->">Back</A>
<!--#else -->
[No HTTP_REFERER is present]
<!--#endif -->

You would probably want to leave that third and fourth line out in practice. And 'Back' could of course be replaced with an image or whatever.

Here is a working example (or as working as it can be): [No HTTP_REFERER is present]

Caveats

This method of creating a Back Button with SSI creates a forward link, i.e. it is not the same as hitting the browser's Back Button and risks causing confusion. Not sure what I'm talking about? I'll try to explain:

• You start on page A and go to page B. The browser's history has A in it. Now click a link to page C. The history is A-B.
• Page C has a back link created with SSI. You click it. (And go forward to B.)
• Now your history says A-B-C and you are on B. If you had used the browser's Back Button the history would be A just like when you first visited B.
• Now if you hit the Back Button you will go back to C. And there is the problem, you went from A to B to C and 'back' to B (with SSI) so how can you be going back to C when you should be going forward?

A Java Script method would go backward in the browser's history and thus keep things more orderly but alas, you need to have Java Script enabled/available on the user's browser. If you decide to use the Java Script method, it is best to do so as a document.write() so the link text only appears when the link will actually work; otherwise a broken link appears and makes you look bad.