function checkEmail( email )
{
    exp = new RegExp( '^([a-zA-Z0-9\\.\\_\\-]+)' + '(\\@)' +
        '([a-zA-Z0-9\\.\\-]+)' + '(\\.)' + '([a-zA-Z]{2,4})$' );

    return exp.exec( email ) != null;
}

function checkForm()
{
    result = true;

    if ( document.form.prefix.options[
        document.form.prefix.selectedIndex].value == '' )
    {
        alert( "Please select your prefix!" );
        document.form.prefix.focus();
        result = false;
    }

    else if ( document.form.firstname.value == "" )
    {
        alert( "Please enter your first name!" );
        document.form.firstname.focus();
        result = false;
    }

    else if ( document.form.lastname.value == "" )
    {
        alert( "Please enter your last name!" );
        document.form.lastname.focus();
        result = false;
    }

    else if ( document.form.address.value == "" )
    {
        alert( "Please enter your address!" );
        document.form.address.focus();
        result = false;
    }

    else if ( document.form.city.value == "" )
    {
        alert( "Please enter your city!" );
        document.form.city.focus();
        result = false;
    }

    else if ( document.form.zip.value == "" )
    {
        alert( "Please enter your zip code!" );
        document.form.zip.focus();
        result = false;
    }

    else if ( document.form.country.options[
        document.form.country.selectedIndex].value == '' )
    {
        alert( "Please select your country!" );
        document.form.country.focus();
        result = false;
    }

    else if ( checkEmail( document.form.email.value ) == false )
    {
        alert( "Please enter a valid email address!" );
        document.form.email.focus();
        result = false;
    }

    return result;
}