var detectableWithVB;

//adapted from http://support.adobe.com/devsup/devsup.nsf/docs/52970.htm/$File/detectplugins.htm
function detectPDF() {
    pluginFound = detectPlugin('Adobe','Acrobat'); 
    // if not found, try to detect with VisualBasic
    if(!pluginFound && detectableWithVB) {
        pluginFound = detectActiveXControl('AcroPDF.PDF.1'); //works for Reader 9
        if(!pluginFound) { 
            pluginFound = detectActiveXControl('PDF.PdfCtrl.5'); //used in most examples
            if(!pluginFound) { 
                pluginFound = detectActiveXControl('PDF.PdfCtrl.6'); //used in some examples
            }
        }
    }
    return pluginFound;
}

function detectPlugin() {
    // allow for multiple checks in a single pass
    var daPlugins = detectPlugin.arguments;
    // consider pluginFound to be false until proven true
    var pluginFound = false;
    // if plugins array is there and not fake
    if (navigator.plugins && navigator.plugins.length > 0) {
        var pluginsArrayLength = navigator.plugins.length;
        // for each plugin...
        for (pluginsArrayCounter=0; pluginsArrayCounter < pluginsArrayLength; pluginsArrayCounter++ ) {
            // loop through all desired names and check each against the current plugin name
            var numFound = 0;
            for(namesCounter=0; namesCounter < daPlugins.length; namesCounter++) {
                // if desired plugin name is found in either plugin name or description
                if( (navigator.plugins[pluginsArrayCounter].name.indexOf(daPlugins[namesCounter]) >= 0) || 
                    (navigator.plugins[pluginsArrayCounter].description.indexOf(daPlugins[namesCounter]) >= 0) ) {
                    // this name was found
                    numFound++;
                }   
            }
            // now that we have checked all the required names against this one plugin,
            // if the number we found matches the total number provided then we were successful
            if(numFound == daPlugins.length) {
                pluginFound = true;
                // if we've found the plugin, we can stop looking through at the rest of the plugins
                break;
            }
        }
    }
    return pluginFound;
} // detectPlugin


// Here we write out the VBScript block for MSIE Windows
if ((navigator.userAgent.indexOf('MSIE') != -1) && (navigator.userAgent.indexOf('Win') != -1)) {
    document.writeln('<script language="VBscript">');

    document.writeln('\'do a one-time test for a version of VBScript that can handle this code');
    document.writeln('detectableWithVB = False');
    document.writeln('If ScriptEngineMajorVersion >= 2 then');
    document.writeln('  detectableWithVB = True');
    document.writeln('End If');

    document.writeln('\'this next function will detect most plugins');
    document.writeln('Function detectActiveXControl(activeXControlName)');
    document.writeln('  on error resume next');
    document.writeln('  detectActiveXControl = False');
    document.writeln('  If detectableWithVB Then');
    document.writeln('     detectActiveXControl = IsObject(CreateObject(activeXControlName))');
    document.writeln('  End If');
    document.writeln('End Function');

    document.writeln('\'and the following function handles QuickTime');
    document.writeln('Function detectQuickTimeActiveXControl()');
    document.writeln('  on error resume next');
    document.writeln('  detectQuickTimeActiveXControl = False');
    document.writeln('  If detectableWithVB Then');
    document.writeln('    detectQuickTimeActiveXControl = False');
    document.writeln('    hasQuickTimeChecker = false');
    document.writeln('    Set hasQuickTimeChecker = CreateObject("QuickTimeCheckObject.QuickTimeCheck.1")');
    document.writeln('    If IsObject(hasQuickTimeChecker) Then');
    document.writeln('      If hasQuickTimeChecker.IsQuickTimeAvailable(0) Then ');
    document.writeln('        detectQuickTimeActiveXControl = True');
    document.writeln('      End If');
    document.writeln('    End If');
    document.writeln('  End If');
    document.writeln('End Function');

    document.writeln('</scr' + 'ipt>');
}
// -->