function mnu_right(browser) {
  ie = "Microsoft Internet Explorer";
  ns = "Netscape";
  os = navigator.platform;
  mac = 'MacPPC'
  if (browser == ns) {
  }
  else {
  }
}

function mnu_over(element){ 
        var el = document.getElementById(element); 
                el.className='menu_over';  
} 
function mnu_out(element){ 
        var el = document.getElementById(element); 
                el.className='menu';    
}
function cambio(abc){
  if (document.getElementById(abc).style.display == 'none') {
    document.getElementById('menu_1').style.display = 'none';
    document.getElementById('menu_2').style.display = 'none';
    document.getElementById('menu_3').style.display = 'none';
    document.getElementById(abc).style.display = 'block';
    document.getElementById(abc).style.style = 'z-index:150';
  }
  else {
    document.getElementById(abc).style.display = 'none';
    document.getElementById(abc).style.style = 'z-index:150';
  }
}