var IE = navigator.appName=="Microsoft Internet Explorer";
    var NS = navigator.appName=="Netscape";
    var bVer = parseInt(navigator.appVersion);




// Time out

function clickIE() {if (document.all) {(message);return false;}}
function clickNS(e) {if
(document.layers||(document.getElementById&&!document.all)) {
if (e.which==2||e.which==3) {(message);return false;}}}
if (document.layers)
{document.captureEvents(Event.MOUSEDOWN);document.onmousedown=clickNS;}
else{document.onmouseup=clickNS;document.oncontextmenu=clickIE;}

document.oncontextmenu=new Function("return false");


function mouseDown(e) {
 var ctrlPressed=0;
 var altPressed=0;
 var shiftPressed=0;
 if (parseInt(navigator.appVersion)>3) {
  if (navigator.appName=="Netscape") {
   var mString =(e.modifiers+32).toString(2).substring(3,6);
   shiftPressed=(mString.charAt(0)=="1");
   ctrlPressed =(mString.charAt(1)=="1");
   altPressed  =(mString.charAt(2)=="1");
   self.status="modifiers="+e.modifiers+" ("+mString+")"
  }
  else {
   shiftPressed=event.shiftKey;
   altPressed  =event.altKey;
   ctrlPressed =event.ctrlKey;
  }
  if (shiftPressed || altPressed || ctrlPressed)
   alert ("Función no permitida");

 }
 return true;
}
if (parseInt(navigator.appVersion)>3) {
 document.onmousedown = mouseDown;
 if (navigator.appName=="Netscape")
  document.captureEvents(Event.MOUSEDOWN);
}