addLoadEvent(function(){
  var filter = $('filter')
  if(filter){
    filter.onchange = function(){
      var f = $('filter')
      var value = f.options[f.options.selectedIndex].value
      DirectoryFilter.show(value)
    }
  }
});
DirectoryFilter = {
  'show': function(v){
    var tables = getElementsByTagAndClassName('table', 'listing')
    for(var i=0;i<tables.length;i++){
      var rows = getElementsByTagAndClassName('tr', null, tables[i])
      var rowNum = 1
      count = 0
      for(var j=0;j<rows.length;j++){
        if(rows[j].firstChild.tagName == 'th' || rows[j].firstChild.tagName == 'TH'){ continue }
        if(!rows[j].style.display == undefined){ continue }
        if(v == 'all' || hasElementClass(rows[j], v) || (v == 'faculty' && (hasElementClass(rows[j], 'middle-school') || hasElementClass(rows[j], 'upper-school')))){ 
          if(document.all){ showElement(rows[j]) }
          else if(!document.all){ rows[j].style.display = 'table-row' }
          removeElementClass(rows[j], 'row1')
          removeElementClass(rows[j], 'row2')
          addElementClass(rows[j], 'row'+rowNum)
          rowNum++
          if(rowNum > 2){ rowNum = 1 }
          count++
        }
        if(v != 'all' && !hasElementClass(rows[j], v) && !(v == 'faculty' && (hasElementClass(rows[j], 'middle-school') || hasElementClass(rows[j], 'upper-school')))){ hideElement(rows[j]) }
      }
      if(count == 0){
        hideElement(tables[i])
      }
      else {
        if(document.all){
          showElement(tables[i])
        }
        else {
          tables[i].style.display='table'
        }
      }
    }
  }
}