Detect PDF Viewer plugins

hasPDFViewer.js

/*
	hasPDFViewer.js
	Version: 1.0.0
	Date: 2015-03-04
	
	(C) 2015 Alessandro Segala
	License: BSD-2-Clause (http://opensource.org/licenses/BSD-2-Clause)
	
	Original author: Ben Kitzelman (http://thecodeabode.blogspot.ca/2011/01/detect-adobe-reader-plugin.html)
*/

function hasPDFViewer() {
	var hasActiveXObject = function(name) {
		try {
			var obj = new ActiveXObject(name)
			if(obj) {
				return true
			}
		}
		catch(e) {}
		
		return false
	}
	
	var hasNavigatorPlugin = function(name) {
		for(key in navigator.plugins) {
			var plugin = navigator.plugins[key]
			if(plugin.name == name) {
				return true
			}
		}
		
		return false
	}
	
	// Does not match IE11+, but IE11+ supports navigator.plugins
	var userAgent = navigator ? navigator.userAgent.toLowerCase() : 'other'
	if(~(userAgent.indexOf('msie'))) {
		// Load the activeX control
		// AcroPDF.PDF is used by version 7 and later
		// PDF.PdfCtrl is used by version 6 and earlier
		return hasActiveXObject('AcroPDF.PDF')
			|| hasActiveXObject('PDF.PdfCtrl')
	}
	else {
		return hasNavigatorPlugin('Adobe Acrobat')
			|| hasNavigatorPlugin('Chrome PDF Viewer')
			|| hasNavigatorPlugin('WebKit built-in PDF')
	}
}

Forked from: https://gist.github.com/benkitzelman/6d4ead05b3d4b80518f3