function switch_big() {
  if(document.getElementById("big").style.visibility != "visible")
    document.getElementById("big").style.visibility = "visible";
  else
    document.getElementById("big").style.visibility = "hidden";
}

function switch_submenu() {
  var oSubMenu = document.getElementById("submenu");

 if(oSubMenu.style.display == "none")
   oSubMenu.style.display = "inline";
 else
   oSubMenu.style.display = "none";
}

var render = {
  init : function() {
    var nBodyHeight = window.innerHeight || document.documentElement.clientHeight || document.body.clientHeight;
    var nHeaderHeight = document.getElementById("header").offsetHeight;
    var nHeaderSHeight = document.getElementById("header_small").offsetHeight;
    var nFooterHeight = document.getElementById("footer").offsetHeight;
    var nMainHeight = nBodyHeight - (nHeaderHeight + nHeaderSHeight + nFooterHeight) - 18;  // 18px margin
    
    document.getElementById("main").style.height = nMainHeight + "px";
    //document.getElementById("navigation").style.height = nMainHeight + "px";
    document.getElementById("content").style.height = nMainHeight + "px";
    document.getElementById("submenu").style.display = "none";
  }
}

window.onload = function() { render.init(); }  
window.onresize = function() { render.init(); }