function showHide(number){ 
  if (document.getElementById("nav" + number).style.display == 'none'){ 
    document.getElementById("nav" + number).style.display = '';
  } else { 
    document.getElementById("nav" + number).style.display = 'none'; 
  } 
  if (number==2){
  document.getElementById("nav3").style.display = 'none'; 
  document.getElementById("nav4").style.display = 'none'; 
  } 
  if (number==3){
  document.getElementById("nav2").style.display = 'none'; 
  document.getElementById("nav4").style.display = 'none'; 
  } 
  if (number==4){
  document.getElementById("nav3").style.display = 'none'; 
  document.getElementById("nav2").style.display = 'none'; 
  } 
}



//sfHover couresty of http://www.htmldog.com (http://www.htmldog.com/articles/suckerfish/dropdowns/)
sfHover = function() {
	var sfEls = document.getElementById("home_nav").getElementsByTagName("li");
	for (var i=0; i<sfEls.length; i++) {
		sfEls[i].onmouseover=function() {
			this.className+=" sfhover";
		}
		sfEls[i].onmouseout=function() {
			this.className=this.className.replace(new RegExp(" sfhover\\b"), "");
		}
	}
}
if (window.attachEvent) window.attachEvent("onload", sfHover);