function FilterObject(blnShow)
{
 this.Show = blnShow;
}

function changeFilter(objBox)
{
 var thisFilter = objBox.value;
 if(catFilter[thisFilter])
 {
  catFilter[thisFilter].Show = (catFilter[thisFilter].Show ? false : true);
 }
 else {catFilter[objBox.value] = new FilterObject(true);}
 $("div[rel='" + objBox.value + "']").css("display",(catFilter[thisFilter].Show ? "block" : "none")); 
 getMarkers(true);
}