function thumbWindow(mypage, myname, w, h, fit_to_screen) {
	
	var props = '';
	var orig_w = w;
	var scroll = '';
	
	// centrado
	var winl = (screen.availWidth - w) / 2;
	var wint = (screen.availHeight - h) / 2;	
	if (winl < 0) { winl = 0; w = screen.availWidth - 6; scroll = 1;}
	if (wint < 0) { wint = 0; h = screen.availHeight - 32; scroll = 1;}
		
	winprops = 'height='+h+',width='+w+',top='+wint+',left='+winl+',scrollbars='+scroll+',resizable=no'
	win = window.open('', myname, winprops)
	win.document.open();
	win.document.write('<html><head>');
	
	// no quiero que se cierre onclick
	/*win.document.write('<scr' + 'ipt type="text/javascr' + 'ipt" language="JavaScr' + 'ipt">');
  	win.document.write("function click() { window.close(); } ");  // bei click  schliessen
  	win.document.write("document.onmousedown=click ");
  	win.document.write('</scr' + 'ipt>');*/
	
	win.document.write('<title>'+myname+'</title></head>');
	win.document.write('<body leftmargin="0" topmargin="0" marginheight="0" marginwidth="0" onBlur="window.close()">');

	if (fit_to_screen) {

		var ns6 = (!document.all && document.getElementById);
		var ie4 = (document.all);
		var ns4 = (document.layers);
	
		if (ns6||ns4) {
						
			sbreite = innerWidth - 23;
			
		} else if (ie4) {			
			
			sbreite = document.body.clientWidth - 5;
			
		}
	
		if (orig_w > sbreite) {
			
			rw = 'width='+sbreite;
			
		} else {
			
			rw = '';
			
		}
		
		win.document.write('<img src="'+mypage+'" alt="'+myname+'" title="'+myname+'" border="0" '+rw+'\></body></html>');
		
	} else {
		
		win.document.write('<img src="'+mypage+'" alt="'+myname+'" title="'+myname+'" border="0" ></body></html>');
		
	}
	
	win.document.close();
	
	if (parseInt(navigator.appVersion) >= 4) {
		win.window.focus();
	}
}