function highlightFilters() {    
    var $filterdealer    = document.getElementById('filterdealer');
    var $filtervenue     = document.getElementById('filtervenue');
    var $filterarea      = document.getElementById('filterarea');
    var $filterdate      = document.getElementById('filterdate');
    var $filterproduct   = document.getElementById('filterproduct');   
    if ( $filterdealer.selectedIndex > 0 ) { $filterdealer.style.backgroundColor = '#ddffdd'; } else { $filterdealer.style.backgroundColor = '#fff'; }
    if ( $filtervenue.selectedIndex > 0 ) { $filtervenue.style.backgroundColor = '#ddffdd'; } else { $filtervenue.style.backgroundColor = '#fff'; }
    if ( $filterarea.selectedIndex > 0 ) { $filterarea.style.backgroundColor = '#ddffdd'; } else { $filterarea.style.backgroundColor = '#fff'; }
    if ( $filterdate.selectedIndex > 0 ) { $filterdate.style.backgroundColor = '#ddffdd'; } else { $filterdate.style.backgroundColor = '#fff'; }
    if ( $filterproduct.selectedIndex > 0 ) { $filterproduct.style.backgroundColor = '#ddffdd'; } else { $filterproduct.style.backgroundColor = '#fff'; }
}

function filterSubmit() {

    document.getElementById('filterform').submit();

}

function filterRemove() {

    var $filterdealer    = document.getElementById('filterdealer');
    var $filtervenue     = document.getElementById('filtervenue');
    var $filterarea      = document.getElementById('filterarea');
    var $filterdate      = document.getElementById('filterdate');
    var $filterproduct   = document.getElementById('filterproduct');   

    $filterdealer.selectedIndex = 0;
    $filtervenue.selectedIndex = 0;
    $filterarea.selectedIndex = 0;
    $filterdate.selectedIndex = 0;
    $filterproduct.selectedIndex = 0;
    
    highlightFilters();
    filterSubmit();
    
}