var randomnumber;
		var x;
		var books;
		
		books = 4;
		
		randomnumber = Math.floor(Math.random() * books);
		randomnumber = randomnumber + 1;
		
		switch(randomnumber)
			{
			case 1:
				document.write('<iframe src="http://www.trifind.net/silverman/2010/3.html" width=728 height=90 frameborder=0 scrolling=no marginwidth=0 marginheight=0></iframe>');
				break;
			case 10:
				document.write('<a href="http://www.trifindsportbenefits.com/" target="_blank"><img src="http://trifind.net/b/gHP-Sport/SS.gif"');
				document.write(' border="0"');
				document.write(' alt="Enhanced Athletic Performance"></a>');
				break;
			case 3:
				document.write('<iframe src="http://www.trifind.net/silverman/2010/2.html" width=728 height=90 frameborder=0 scrolling=no marginwidth=0 marginheight=0></iframe>');
				break;
			case 4:
				document.write('<iframe src="http://www.trifind.net/silverman/2010/1.html" width=728 height=90 frameborder=0 scrolling=no marginwidth=0 marginheight=0></iframe>');
				break;
			}