function getQueryVariable(variable) {
  var query = window.location.search.substring(1);
  var vars = query.split("&");
  for (var i=0;i<vars.length;i++) {
    var pair = vars[i].split("=");
    if (pair[0] == variable) {
      return pair[1];
    }
  } 
}

function toggleLayer(whichLayer)
{
	if (document.getElementById)
	{
		// this is the way the standards work
		var style2 = document.getElementById(whichLayer).style;
		style2.display = style2.display? "":"none";
	}
	else if (document.all)
	{
		// this is the way old msie versions work
		var style2 = document.all[whichLayer].style;
		style2.display = style2.display? "":"none";
	}
	else if (document.layers)
	{
		// this is the way nn4 works
		var style2 = document.layers[whichLayer].style;
		style2.display = style2.display? "":"none";
	}
	//bouton = document.getElementById("Bouton"+whichLayer);
	// image = style2.display?"/images/showicon.png":"/images/hideicon.png";
	//bouton.src=image;

}