Software Público Brasileiro

function horizontal() {
  
    var navItems = document.getElementById("menu_dropdown").getElementsByTagName("li");
     
    for (var i=0; i< navItems.length; i++) {
       if(navItems[i].className == "submenu")
       {
          if(navItems[i].getElementsByTagName('ul')[0] != null)
          {
             navItems[i].onmouseover=function() {this.getElementsByTagName('ul')[0].style.display="block";this.style.backgroundColor = "#f9f9f9";}
             navItems[i].onmouseout=function() {this.getElementsByTagName('ul')[0].style.display="none";this.style.backgroundColor = "#FFF";}
          }
       }
    }
  
}