import flash.system.Capabilities;

var flashPlayerMajorVersion:int;

trace("Getting Flash Player version ...");
var versionString:String = Capabilities.version;
var pattern:RegExp = /^(\w*) (\d*),(\d*),(\d*),(\d*)$/;
var result:Object = pattern.exec(versionString);
if (result != null) {
	trace("input: " + result.input);
	trace("platform: " + result[1]);
	flashPlayerMajorVersion = int(result[2]);
	trace("flashPlayerMajorVersion: " + flashPlayerMajorVersion);
	trace("minorVersion: " + result[3]);    
	trace("buildNumber: " + result[4]);
	trace("internalBuildNumber: " + result[5]);
} else {
	trace("Unable to match RegExp.");
}

// Example output ...
//
// Getting Flash Player version ...
// input: WIN 10,1,52,14
// platform: WIN
// flashPlayerMajorVersion: 10
// minorVersion: 1
// buildNumber: 52
// internalBuildNumber: 14

import flash.system.Capabilities;

var flashPlayerMajorVersion:int;

trace("Getting Flash Player version ...");
var versionString:String = Capabilities.version;
var pattern:RegExp = /^(\w*) (\d*),(\d*),(\d*),(\d*)$/;
var result:Object = pattern.exec(versionString);
if (result != null) {
	trace("input: " + result.input);
	trace("platform: " + result[1]);
	flashPlayerMajorVersion = int(result[2]);
	trace("flashPlayerMajorVersion: " + flashPlayerMajorVersion);
	trace("minorVersion: " + result[3]);    
	trace("buildNumber: " + result[4]);
	trace("internalBuildNumber: " + result[5]);
} else {
	trace("Unable to match RegExp.");
}

This code separates out the Flash Player Platform, Major Version number and Minor Version numbers.

AS3 Get Flash Player Version Number (inc. Major and Minor Numbers)

regex, flash, regexp

ActionScript 3