if (!document.getElementById)
    document.getElementById = function() { return false; }

function initmenu(){
	
    var browser = navigator.userAgent;
    browser = browser.toLowerCase();
    browser = browser.split('/');
    version = browser[1].split('.')
        
    var no = "nobackground";
    var menu = document.getElementById('menu');
    var lis = menu.getElementsByTagName( 'li' );
    var uls = menu.getElementsByTagName( 'ul' );
    
    
    for (i=0; i<lis.length; i++){
    
        var ul = lis.item(i).getElementsByTagName( 'ul' );
        
        if ( ul.item(0) ){
            /* Internet Explorer y Opera6 */
            if ( document.all || ( browser[0]=='opera' && version[0]==6 )  ){
                lis.item(i).onmouseover = visible;
                lis.item(i).onmouseout = hidden;
                lis.item(i).onkeyup = visible;
            /* otro Browser */
            }else if( document.getElementById ){
                lis.item(i).addEventListener("mouseover",visible,true);
                lis.item(i).addEventListener("mouseout",hidden,true);
                lis.item(i).addEventListener("blur",hidden,true);
                lis.item(i).addEventListener("focus",visible,true);
                }
            }
                
        }
    }
    
function hidden(){
    var ul = this.getElementsByTagName( 'ul' );
    ul.item(0).style.visibility = "hidden";
    }
    
function visible(){
    var ul = this.getElementsByTagName( 'ul' );
    ul.item(0).style.visibility = "visible";
    }