var username;
function set_username(obj) {
        username = obj.username;
}   

setmenu = function() {
    if (username) {
        document.getElementById('welcome').innerHTML = 'ようこそ、' + username + 'さん';
        document.getElementById('entry').innerHTML = '<a href="/contents/company/entryinfo.html" class="headermenu">登録変更</a>';
        document.getElementById('login').innerHTML = '<a href="/logout" class="headermenu">ログアウト</a>';
    }
}

if (window.addEventListener)
    window.addEventListener("load", setmenu, false);
else if (window.attachEvent)
    window.attachEvent("onload", setmenu);
else window.onload = setmenu;