When the .NET Framework 3.5 is installed, the MSI adds “.NET CLR” and the version number to the UserAgent string. The following example shows a script embedded in a simple HTML page. The script searches the UserAgent string to determine whether the .NET Framework 3.5 is installed, and displays a status message on the results of the search.
<HTML> <HEAD> <TITLE>Test for the .NET Framework 3.5</TITLE> <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=utf-8" /> <SCRIPT LANGUAGE="JavaScript"> <!-- var dotNETRuntimeVersion = "3.5.0.0"; function window::onload() { if (HasRuntimeVersion(dotNETRuntimeVersion)) { result.innerText = "This machine has the correct version of the .NET Framework 3.5." } else { result.innerText = "This machine does not have the correct version of the .NET Framework 3.5." + " The required version is v" + dotNETRuntimeVersion + "."; } result.innerText += "\n\nThis machine's userAgent string is: " + navigator.userAgent + "."; } // // Retrieve the version from the user agent string and // compare with the specified version. // function HasRuntimeVersion(versionToCheck) { var userAgentString = navigator.userAgent.match(/.NET CLR [0-9.]+/g); if (userAgentString != null) { var i; for (i = 0; i < userAgentString.length; ++i) { if (CompareVersions(GetVersion(versionToCheck), GetVersion(userAgentString[i])) <= 0) return true; } } return false; } // // Extract the numeric part of the version string. // function GetVersion(versionString) { var numericString = versionString.match(/([0-9]+)\.([0-9]+)\.([0-9]+)/i); return numericString.slice(1); } // // Compare the 2 version strings by converting them to numeric format. // function CompareVersions(version1, version2) { for (i = 0; i < version1.length; ++i) { var number1 = new Number(version1[i]); var number2 = new Number(version2[i]); if (number1 < number2) return -1; if (number1 > number2) return 1; } return 0; } --> </SCRIPT> </HEAD> <BODY> <div id="result" /> </BODY> </HTML>
If the search for the “.NET CLR ” version is successful, the following type of status message appears:
This machine has the correct version of the .NET Framework 3.5.
This machine’s userAgent string is: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0; SLCC1; .NET CLR 2.0.50727; .NET CLR 1.1.4322; InfoPath.2; .NET CLR 3.0.590; .NET CLR 3.5.20726; MS-RTC LM 8).
Otherwise, the following type of status message appears:
This machine does not have the correct version of the .NET Framework 3.5. The required version is v3.5.0.0.
This machine’s userAgent string is: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0; SLCC1; .NET CLR 2.0.50727; .NET CLR 1.1.4322; InfoPath.2; .NET CLR 3.0.590; MS-RTC LM 8).
Source of this post : MSDN