Developer :: Flash Resources :: Make your Flash application backwards compatible

By Tom Fitzgerald

Writing Flash programs can be challenging because not all web browsers and computers are the same. Flash provides a quality presentation most of the time everything works fine on different platforms as long the Flash plug-in is installed. But what if you write an application for Version 8 and the viewer has Version 7? The short answer: it is a debacle. The Flash quality we have lauded here disappears in a flash (no pun intended)

What is the solution? With a little ingenuity, the Flash player version can be readily identified and then the content for the user can be tailored based on the version that the end user has. A good example of this technique can be seen on www.QACChamber.com . The navigation on the left and the top bar uses this technique. What it does is after it finds the version of Flash it will either show the more advanced animated version (if they have Version 8 or higher) or show a static image (if they have Version 7 or lower). This technique of designing Flash has been a real difference maker for our clients. Our designers have seen too many web sites where this Flash has not been used, leading to disastrous consequences for often unwitting client that does not realize the problem because the web site looks just fine on the client's browser who has Version 8. Our web designers have also seen too many web sites where a older version is recognized by the web site which directs the user to Macromedia's site to get the latest version. How many end users are going to go through the process of loading new software just to view the web site? Certainly, some will but some will not, and this means lost customers for the client. Admittedly, this approach is sometimes required for some full Flash web sites for technical reasons that need not be addressed here but but if you are using Flash as a single weapon in a larger arsenal as our web site designers typically do, then this technique will suit provide a far better outcome for the client.

Now, on to the technical explanation of how this technique is developed. In the example illustrated below, we have created two frames, in the first frame has the static image for an older player that cannot handle Version 8's animation, and anti-aliased for text features. So then in frame number 2, we put in the movie clip with the sophisticated animation imagery that Version 8 can receive.

Step by Step

From there, in the first frame, we put the following into the Action Frame (Hit F9 if it's not visible).

playerVersion = System.capabilities.version;
temp = substring(playerVersion, 5, 1);

if(temp >= 8) {
play();
} else {
stop();
}

To explain what this does; line by line.

playerVersion = System.capabilities.version;

This references the System.capabilities.version variable and stores it into a variable we created called playerVersion. The value of player version is now ...

WIN 8,0,22,0

Easy enough, but we are not home yet. We need to get the major version number (Version 8 in this case) so we can do an 'if..then' statement. So now onto the next line.

temp = substring(playerVersion, 5, 1);

This uses the substring function and references the playerVersion variable. It then takes the fifth letter and stores it in the variable temp. The "...5,1)" means to take the fifth character and the 1 means to only take 1 character. So now we have the major version number in a variable.

if(temp >= 8) {
play();
} else {
stop();
}

Now we say essentially iIf the version is 8 or higher, move to frame two, if it is less than Version 8, stay on the first frame. This will enable us to have the basic image on the first frame and the high tech stuff on the second frame.

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