function page_lock () {
    if (navigator.userAgent.match(/MSIE/)) {
        document.getElementById('page-lock-div').style.position = 'absolute';
        //document.getElementById('page-lock-div').style.background = 'none';
        //document.getElementById('page-lock-div').style.backgroundImage = 'url(/media/img/lock-background.gif)';
    }
    document.getElementById('page-lock-div').style.display = 'block';
}
function page_unlock () {
    document.getElementById('page-lock-div').style.display = 'none';
}

function show_login () {
    page_lock();
    if (navigator.userAgent.match(/MSIE/)) {
        document.getElementById('login-form-div').style.position = 'absolute';
    }
    document.getElementById('login-form-div').style.display = 'block';
    document.getElementById('login-email').focus();
}

function hide_login () {
    page_unlock();
    document.getElementById('login-form-div').style.display = 'none';
}