code:

// Searches the registry for all versions of installed Java runtimes and uninstalls them

// Terminates all running IE instances
killProcesses("iexplore.exe");

var shell = new ActiveXObject("WScript.Shell");
keyPath = "SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Uninstall";
HKLM = 0x80000002;

// Enumerate all the subkeys of the Uninstall registry
oLoc = new ActiveXObject("WbemScripting.SWbemLocator");
oSvc = oLoc.ConnectServer(null, "root\\default");
oReg = oSvc.Get("StdRegProv");
oMethod = oReg.Methods_.Item("EnumKey");
oInParam = oMethod.InParameters.SpawnInstance_();
oInParam.hDefKey = HKLM;
oInParam.sSubKeyName = keyPath;
colItems = oReg.ExecMethod_(oMethod.Name, oInParam);

var x = colItems.sNames.toArray()

for (i=0; i<x.length; i++)
{
	try
	{
		displayName = shell.RegRead("HKLM\\" + keyPath + "\\" + x[i] + "\\DisplayName");

		// Try to find all old Java runtimes no matter how it was called back then
		if (displayName.indexOf("Java(TM) 6 Update") == 0 || 
			displayName.indexOf("Java 2 Runtime Environment") == 0 || 
			displayName.indexOf("J2SE Runtime Environment") == 0 || 
			displayName.indexOf("Java(TM) SE Runtime Environment") == 0
			)
		{
			displayVersion = shell.RegRead("HKLM\\" + keyPath + "\\" + x[i] + "\\DisplayVersion");
			WScript.Echo(displayName);
			WScript.Echo(displayVersion);

			// If this installation is not Java 7, uninstall it
			if (displayName.indexOf("Java(TM) 7"))
			{
				uninstall = shell.RegRead("HKLM\\" + keyPath + "\\" + x[i] + "\\UninstallString");
				uninstallString = uninstall + " /qb";
				WScript.Echo(uninstallString);

				// If the uninstallstring is using /i as an argument we need to replace it with /x
				// MsiExec.exe /I{7148F0A8-6813-11D6-A77B-00B0D0142100} /qb
				if (uninstallString.toLowerCase().indexOf('/i') != -1)
				{
					uninstallString = uninstallString.replace(/\/i/i, '/x');
					WScript.Echo('=> ' + uninstallString);
				}

				WScript.Echo(shell.Run(uninstallString, 1, true));
			}
		}
	}
	catch (e)
	{
	}
}

function killProcesses(processName)
{
	debug("Trying to kill all instances of " + processName);

	var wmiService = GetObject("winmgmts:\\\\.\\root\\cimv2");
	var colItems = wmiService.ExecQuery("Select * from Win32_Process Where Name = '" + processName + "'", "WQL", 0x30);

	var enumItems = new Enumerator(colItems);
	for (; !enumItems.atEnd(); enumItems.moveNext())
	{
		var objItem = enumItems.item();

		debug("Killing " + processName);
		objItem.terminate();
	}
}

function debug(errorMessage)
{
	if (WScript.FullName.indexOf("cscript") != -1)
		WScript.Echo(errorMessage);
}