function preLoadForm(arrEvents)
{
    var form = document.forms[0];
    if (arrEvents.length > 0)
    {
        // there is at least one event... let's high light it
        if (form.disaster.options.length > 0)
        {
            form.disaster.selectedIndex = 0;
            enableProperTiers(form.disaster.value);
        }
    }
    else
    {
        // There were no events at all.  Let's just go
        // ahead and disable the select box and submit button.
        form.disaster.disabled = true;
        form.elements["continue"].disabled = true;
    }
}

function validateForm(form)
{
    if (form.disaster.value == "")
    {
        alert ("You must select an Event.");
        return false;
    }
    
    var tier_val = 0;
    for (var i=0; i < form.tier.length; i++)
    {
        if (form.tier[i].checked)
        {
            tier_val = form.tier[i].value;
        }
    }
    if (tier_val == 0)
    {
        alert ("You must select an Interface.");
        return false;
    }
    
    return true;
}

function enableProperTiers(event)
{
    var form = document.forms[0];
    var checkedIndex = 0;

    if (form.event_type.value == 'baseline')
    {
        arrEvents = arrBaselines;
    }
    else
    {
        arrEvents = arrDisasters;
    }

    for (var i=0; i<arrEvents.length; i++)
    {
        if (arrEvents[i][1] == event)
        {
            for (var j=0; j<arrEvents[i][2].length; j++)
            {
                // try to preserve the tier that was previously chosen
                if (form.tier[j].checked)
                {
                    checkedIndex = j;
                }
                form.tier[j].checked = false;
                form.tier[j].disabled = !arrEvents[i][2][j];
            }

            // check the previously checked tier if it's not disabled
            if (!form.tier[checkedIndex].disabled)
            {
                form.tier[checkedIndex].checked = true;
            }
            else
            {
                // it was disabled... find the first available
                for (var j=0; j<arrEvents[i][2].length; j++)
                {
                    if (!form.tier[j].disabled)
                    {
                        form.tier[j].checked = true;
                        break;
                    }
                }
            }
            break;
        }
    }
}

function reloadEventList(event_type)
{
    var form = document.forms[0];
    var arrEvents = new Array();
    
    if (event_type == 'baseline')
    {
        form.event_type.value = 'baseline';
        arrEvents = arrBaselines;
    }
    else
    {
        form.event_type.value = 'disaster';
        arrEvents = arrDisasters;
    }
    
    // Clear out the current list of options
    while (form.disaster.options.length > 0)
    {
        form.disaster.remove(0);
    }
    
    // load new options for this event type
    for (var i=0; i<arrEvents.length; i++)
    {
        var newOption = new Option(arrEvents[i][0], arrEvents[i][1]);
        form.disaster.options[form.disaster.options.length] = newOption;
    }
    
    preLoadForm(arrEvents);
}