var plugins = {
	hasAcrobat:function() {
		if (!window.ActiveXObject) return false;
		try { if (new ActiveXObject('AcroPDF.PDF')) return true;}
		catch (e) {}
		try { if (new ActiveXObject('PDF.PdfCtrl')) return true;}
		catch (e) {}
		return false;
	},
	hasFlash: function() {
		if (!window.ActiveXObject) return false;
		try {if (new ActiveXObject('ShockwaveFlash.ShockwaveFlash')) return true;}
	    	catch (e) { return false;}
	},
	hasJava: function() {
		return (!navigator.javaEnabled());
	},
	hasQuickTime: function() {
		if (!window.ActiveXObject) return false;
		try { if (new ActiveXObject('QuickTime.QuickTime')) return true;}
		catch (e) {}
		try {if(new ActiveXObject('QuickTimeCheckObject.QuickTimeCheck')) return true;}
		catch (e) {};
		return false;
	},
	hasRealPlayer: function() {
		if (!window.ActiveXObject) return false;
	    	var definedControls = [
			'rmocx.RealPlayer G2 Control',
			'rmocx.RealPlayer G2 Control.1',
			'RealPlayer.RealPlayer(tm) ActiveX Control (32-bit)',
			'RealVideo.RealVideo(tm) ActiveX Control (32-bit)',
			'RealPlayer'
		];
		for (var i = 0; i < definedControls.length; i++) {
			try {if(new ActiveXObject(definedControls[i])) return true;}
			catch (e) {continue;}
		}
		return false;
	},
	hasShockwave: function() {
		if (!window.ActiveXObject) return false;
	    	try {if(new ActiveXObject(’SWCtl.SWCtl’)) return true;}
		catch (e) {return false;}
	},
	hasWMP: function() {
		if (!window.ActiveXObject) return false;
	  	try {if(new ActiveXObject(’WMPlayer.OCX’)) return true;}
		catch (e) { return false;}
	}
}

finding plugins in IE

JavaScript