// open/close span
function plop(obj)
{
  if(document.getElementById(obj+'_bis').style.display == "none")
  {
    document.getElementById(obj+'_bis').style.display = "";
  } else {
    document.getElementById(obj+'_bis').style.display = "none";
  }
}

// mad button
function moveIt() {
	var currX = document.getElementById("bt1").offsetLeft;
	var currY = document.getElementById("bt1").offsetTop;
	do
	{
		var x = Math.floor(Math.random()*200);
		var y = Math.floor(Math.random()*200);
	} while ( ((x > currX - 50) && (x < currX + 100)) || ((y > currY - 25) && (y < currY + 50)) )
	document.getElementById("bt1").style.marginLeft = x;
	document.getElementById("bt1").style.marginTop  = y;
}