Future-Proofing Flash Player Detection Scripts
Created
11 July 2005
Requirements
User level
Intermediate
Each new release of Macromedia Flash Player brings opportunities to create even better experiences. One of the most challenging aspects of deploying Flash content is building a robust detection script that withstands the test of time. The upcoming release of Flash Player, codenamed "Maelstrom," introduces some new features which make detection and installation a great deal easier than before. After it is released, we will provide a comprehensive guide to detecting and installing Flash Player on your website.
In the meantime, however, as the Flash Player team performs ongoing compatibility testing, we've noticed that some popular sites perform player detection in such a way that visitors with Flash Player versions greater than the required version are not permitted to view the content. This prevents our quality assurance team and our beta testing community from being able to discover compatibility issues proactively with the new version of Flash Player. Moreover, detection scripts that aren't updated by the time Macromedia releases Flash Player 8 will prevent users who have the latest version from entering your site.
Mending your detection scripts, if it is necessary, can be done easily and quickly and tested for virtually all script- or SWF-based detection scripts that encompass all versions. Doing so will simplify detection on your site and ensure that you don't unnecessarily shut out visitors.
This article covers two important topics:
- Checking and, if necessary, updating your existing detection scripts to ensure that they function properly when visitors who have Flash Player 8 begin frequenting your website
- Script-based detection of the Flash Player minor revision in Microsoft Internet Explorer
Checking for More Than Just the Version You Need
This problematic situation, which shuts out visitors who have versions of Flash Player greater than the one for which you are checking, can be easily located in your detection script. Look for areas where version numbers are checked and parse the code in your head to make sure that, if version 8 is passed into the script, detection evaluates successfully. If not, you've identified areas that need to be modified.
For example, in most script- and SWF-based detection schemes, playerVersion represents the version of Flash Player on the visitor's computer and requiredVersion represents the version required to view the site content. Instead of permitting visitors only where playerVersion == requiredVersion to enter, detection should allow entry to visitors where playerVersion >= requiredVersion.
Here's an example of a JavaScript detection script with the problematic section highlighted:
function getFlashVersion() {
var agent = navigator.userAgent.toLowerCase();
if (agent.indexOf("mozilla/3") != -1 && agent.indexOf("msie") == -1) {
flashVersion = 0;
}
// NS3+, Opera3+, IE5+ Mac (support plugin array): check for Flash plugin in plugin array
if (navigator.plugins != null && navigator.plugins.length > 0) {
var flashPlugin = navigator.plugins['Shockwave Flash'];
if (typeof flashPlugin == 'object') {
if (flashPlugin.description.indexOf('7.') != -1) flashVersion = 7;
else if (flashPlugin.description.indexOf('6.') != -1) flashVersion = 6;
else if (flashPlugin.description.indexOf('5.') != -1) flashVersion = 5;
else if (flashPlugin.description.indexOf('4.') != -1) flashVersion = 4;
else if (flashPlugin.description.indexOf('3.') != -1) flashVersion = 3;
}
}
}
The final statements which check for Flash don't take into account versions of Flash Player greater than 7. You could simply add another line for Flash Player 8, but that would only solve the problem until the next version arrives.
Here is an amended example of the same script that would run with any future versions (changes are highlighted):
function getFlashVersion() {
var agent = navigator.userAgent.toLowerCase();
flashVersion = 0;
if (agent.indexOf("mozilla/3") != -1 && agent.indexOf("msie") == -1) {
flashVersion = 0;
}
// NS3+, Opera3+, IE5+ Mac (support plugin array): check for Flash plugin in plugin array
if (navigator.plugins != null && navigator.plugins.length > 0) {
var flashPlugin = navigator.plugins['Shockwave Flash'];
if (typeof flashPlugin == 'object') {
for (i=25;i>0;i--) {
if (flashPlugin.description.indexOf(i+'.') != -1){
flashVersion = i;
}
}
}
}
}
This example solves the problem by checking for all possible versions of Flash Player, rather than just the ones you know about. However, this is just one of many workarounds that developers have implemented. The key thing to learn from this example is never to depend on a client's returning a specific version number. You can count on the version of Flash Player you know today to change within the next 18 months.
This example also illustrates the two most common problems found in player-detection scripts. First, it does not properly detect the type of browser and version of Flash Player that the client is running. Second, it does not account for versions of Flash Player the may exist in the future. Now that you have seen the most common mistakes, let's explore a complete solution.
The Right Way to Detect
In order to detect the existence of Flash Player at all, you will need to use small amounts of JavaScript and VBScript. The following script determines the existence and version information of the Flash Player ActiveX control:
<script language="VBScript">
<!-- // Visual basic helper required to detect Flash Player ActiveX control version information
Function VBGetSwfVer(i)
on error resume next
Dim swControl, swVersion
swVersion = 0
set swControl = CreateObject("ShockwaveFlash.ShockwaveFlash." + CStr(i))
if (IsObject(swControl)) then
swVersion = swControl.GetVariable("$version")
end if
VBGetSwfVer = swVersion
End Function
// -->
</script>
By calling the VBGetSwfVer(i) function with the required major version, you will locate two important pieces of information–the existence of Flash Player and its version:
- swControl: true or false, depending on whether Flash Player is installed or not
- swVersion: full version string (for example, "WIN 7,0,14,0") if Flash Player is installed
The following script determines the existence and version information of the Flash Player plug-in. This applies to Netscape, Firefox, Mozilla, Safari, Opera, and all other browsers that support the Netscape Plug-in API and a way to interrogate it using browser scripting:
<SCRIPT LANGUAGE="JavaScript" type="text/javascript">
<!-- // Detect Client Browser type
var isIE = (navigator.appVersion.indexOf("MSIE") != -1) ? true : false;
var isWin = (navigator.appVersion.toLowerCase().indexOf("win") != -1) ? true : false;
var isOpera = (navigator.userAgent.indexOf("Opera") != -1) ? true : false;
// JavaScript helper required to detect Flash Player PlugIn version information
function JSGetSwfVer(i){
// NS/Opera version >= 3 check for Flash plugin in plugin array
if (navigator.plugins != null && navigator.plugins.length > 0) {
if (navigator.plugins["Shockwave Flash 2.0"] || navigator.plugins["Shockwave Flash"]) {
var swVer2 = navigator.plugins["Shockwave Flash 2.0"] ? " 2.0" : "";
var flashDescription = navigator.plugins["Shockwave Flash" + swVer2].description;
descArray = flashDescription.split(" ");
tempArrayMajor = descArray[2].split(".");
versionMajor = tempArrayMajor[0];
if ( descArray[3] != "" ) {
tempArrayMinor = descArray[3].split("r");
} else {
tempArrayMinor = descArray[4].split("r");
}
versionMinor = tempArrayMinor[1] > 0 ? tempArrayMinor[1] : 0;
flashVer = parseFloat(versionMajor + "." + versionMinor);
} else {
flashVer = -1;
}
}
// MSN/WebTV 2.6 supports Flash 4
else if (navigator.userAgent.toLowerCase().indexOf("webtv/2.6") != -1) flashVer = 4;
// WebTV 2.5 supports Flash 3
else if (navigator.userAgent.toLowerCase().indexOf("webtv/2.5") != -1) flashVer = 3;
// older WebTV supports Flash 2
else if (navigator.userAgent.toLowerCase().indexOf("webtv") != -1) flashVer = 2;
// Can't detect in all other cases
else {
flashVer = -1;
}
return flashVer;
}
/ -->
</script>
After you determine which browser your script is running, run through each of these scripts until you find the latest version of the player installed.
The following script starts with a high version number (25) and runs through the proper script for each potential version to determine if it exists on the client. Once the script gets a valid return value, it sets the value of versionStr to the installed version:
// loop backwards through the versions until we find the newest version
for (i=25;i>0;i--) {
if (isIE && isWin && !isOpera) {
versionStr = VBGetSwfVer(i);
} else {
versionStr = JSGetSwfVer(i);
}
At this point you can take this value and make sure your content can be displayed properly in the browser. For example, if your content requires Flash Player 6r65, you could use the following script in conjunction with the scripts above to determine if the client has Flash Player and the proper version:
// If called with no parameters this function returns a floating point value
// which should be the version of the Flash Player or 0.0
// ex: Flash Player 6r65 returns 6.65
// If called with reqMajorVer, reqMinorVer this function returns true if that version or greater is installed
function DetectFlashVer(reqMajorVer, reqMinorVer)
{
reqVer = parseFloat(reqMajorVer + "." + reqMinorVer);
// loop backwards through the versions until we find the newest version
for (i=25;i>0;i--) {
if (isIE && isWin && !isOpera) {;
versionStr = VBGetSwfVer(i);
} else {
versionStr = JSGetSwfVer(i);
}
if (versionStr == -1) {
return false;
} else if (versionStr != 0) {
if(isIE && isWin && !isOpera) {
tempArray = versionStr.split(" ");
tempString = tempArray[1];
versionArray = tempString .split(",");
versionMajor = versionArray[0];
versionMinor = versionArray[2];
versionString = versionMajor + "." + versionMinor;
versionNum = parseFloat(versionString);
} else {
versionNum = versionStr;
}
return (versionNum >= reqVer ? true : false );
}
}
return (reqVer ? false : 0.0);
}
To detect for a specific version of the player, you would call DetectFlashVer(reqMajorVer, reqMinorVer). When calling DetectFlashVer(), pass it a number for reqMajorVer and reqMinorVer. For example, if you want to make sure the end user has Flash Player 6r65 you would enter:
var hasCorrectVersion = DetectFlashVer(6, 65);
If the client has the correct major and minor version (or greater) the variable hasCorrectVersion will equal true. If Flash Player is not installed or the version does not meet the requirements you have specified, it will return false. In addition, if you call DetectFlashVer() with no parameters, you will get a value for the installed player version. If the client has Flash Player 6r65 installed, calling DetectFlashVer() will return "6.65".
Once you complete your script, you will know everything you need to perform proper player detection: whether Flash Player is installed and what version it is. Now your code is future-proof!
