function showHideDiv(divName)
{
    if(document.getElementById(divName))
    {       
        var control = document.getElementById(divName);
        
        if(control.style.display != 'none')
        {
            control.style.display = 'none';
        }   
        else
        {
        control.style.display = 'block';
        }
        
    }
}