function DropMenu() {
  if(navigator.appVersion.indexOf("MSIE") == -1) return;
  
  var menu, grp, cl1, cl2;
  
  menu = document.getElementById("mainmenu");
  if(menu) {
    grp = menu.getElementsByTagName("LI");
    if(grp) {
      for(var i=0; i < grp.length; i++) {
        grp[i].onmouseover = function() {
          cl1 = this.className;
          if(cl1) {
            cl2 = cl1 + ' menuhover';
          } else {
            cl2 = 'menuhover';
          }
          this.className = cl2;
        }
        grp[i].onmouseout = function() {
          cl1 = this.className;
          if(cl1) {
            cl2 = cl1.replace(/\s*menuhover/, '');
          } else {
            cl2 = '';
          }
          this.className = cl2;
        }
      }
    }
  }
}