Originally, to detect the Flash Plugin, it took complex JavaScript which took ages to code. This didn't always work because not all browsers are JavaScript enabled. This tutorial explores a way to detect if someone viewing a webpage has the plugin, using Flash itself.

Check it out the sniffer in action here.

How it works

For this to work, the index.html file (default file) must include two main things:

1. An HTML Meta Tag
2. A small Flash file

The meta tag refreshes the HTML file after a certain number of seconds, and goes to the non_flash file. Here is the coding:

<META HTTP-EQUIV="Refresh" CONTENT="seconds_until_refresh; URL=non_flash_url">

This is placed in the head of the document.

Note: Make sure you do not change any of the coding (ie quotation marks etc) except for the number of seconds (replace seconds_until_refresh), 5-10 is a good amount, and the next URL (replace non_flash_url). If you change anything else, it may not work

The aim of this flash file is to send the user to the flash version of the site when it loads. If the user does not have the Flash Plugin then obviously it won't work and the meta tag will take over and go to the non-flash site. In a new flash file, edit the size of the movie (Ctrl+M or Modify>Movie). Change the width and height both to 18, the smallest possible size.

In the first frame, in the actions tab, add:

Get URL ("url_for_the_flash_file")

Place the SWF file into the same document as the meta tag and save as the default file (index.html) and voila, a fail-safe Flash Plugin detector.

Whichever version of Flash you design the .swf file in, will be the lowest version required to view your Flash site. Too easy!!!

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