var current_show_id = 0;

function onload_intro (lang)
{
	ShowScreen(1, lang);
}

function ShowScreen (id, lang)
{
	var ctl_hide = 'option_' + current_show_id + '_text';
	var ctl_show = 'option_' + id + '_text';
	if (ctl_hide != ctl_show)
	{
		if (current_show_id != 0)
			DisplayItem(ctl_hide, 'none');
			
		DisplayItem(ctl_show, 'inline');
		
		var image = document.getElementById('intro_exp_image');
		image.src = '';
		image.src = 'images/intro_' + id + '_' + lang + '.png';
		
		var link_sel = document.getElementById('option_' + id + '_link');
		link_sel.className = link_sel.className + ' intro_sel';
		if (current_show_id != 0)
		{
			var link_uns = document.getElementById('option_' + current_show_id + '_link');
			link_uns.className = link_uns.className.replace(' intro_sel', '');
		}
		current_show_id = id;
	}
}

function addBk (control, image)
{
    control.style.backgroundImage = "url('images/" + image + "')";
}

function removeBk (control)
{
    control.style.backgroundImage = 'none';
}

function checkLoginFields()
{
    var login = document.login_form.username;
    var pwd   = document.login_form.pwd;
    if (login.value == '')
    {
        login.focus();
    }
    else if (pwd.value == '')
    { 
        pwd.focus(); 
    }
    else 
    {
        document.getElementById('login_go').style.visibility = 'hidden'; 
        document.login_form.submit();
    }
    return false;
}

function checkEmailField()
{
    var email = document.pwd_lost_form.address;
    if (email.value == '')
    {
        email.focus();
    } 
    else
    {
        document.getElementById('email_go').style.visibility = 'hidden'; 
        document.pwd_lost_form.submit(); 
    }
    return false; 
}

function CheckReturn (e)
{
	var key;
	if (window.event) // IE
	{
		key = e.keyCode;
	}
	else if (e.which)
	{
		key = e.which;
	}
	
	if (key != 13)
		return false;
		
	return checkLoginFields();
}