function eraseDef(txt)
{
  var doErase = (!txt.erased && txt.value == txt.defaultValue);
  if(doErase) {
    txt.value = '';
    txt.select();
  }
  txt.erased = true;
  return doErase;
}

function toggle(element) {

if (document.getElementById(element).style.display == "none") {
document.getElementById(element).style.display = "";
} else {
document.getElementById(element).style.display = "none";
}


if (document.getElementById(element+2).style.display == "none") {
document.getElementById(element+2).style.display = "";
} else {
document.getElementById(element+2).style.display = "none";
}
}

function addNumber(Num0,Num) {
	
if (Num0 != null) {
}else {
Num0=0;
}
var a = Num0;
var b = Num;

return betu2.value = alert( Number(a) + Number(b) );	
}