var currentItem = '';

function showhide(item) {
    if (currentItem != '') {
        var currentObject = document.getElementsByName(currentItem);
        if (currentItem == item && currentObject.item(0).style.display == 'none')
        {
            currentObject.item(0).style.display = 'block';
        }
        else
        {
            currentObject.item(0).style.display = 'none';
        }
    }
    
    if (item != currentItem)
    {
        var newObject = document.getElementsByName(item);
        newObject.item(0).style.display = 'block';
    }

    currentItem = item;   
}