function request_object() {
// controleren welk request object aangemaakt moet worden
   var object;
   if(window.XMLHttpRequest){
      object = new XMLHttpRequest();
   } else if(window.ActiveXObject) {
      object = new ActiveXObject("Microsoft.XMLHTTP");
   } else {
      alert('Kan geen Request object maken!');
   }
   return object;
}

// Nieuw request object aanmaken
var RQObject = new request_object();
var client_id = 0;

function request_cat(id) {
	RQObject.open('GET', 'getZoek.php?id='+id); 
	RQObject.onreadystatechange = handle_cat;
	RQObject.setRequestHeader( "If-Modified-Since", "Sat, 1 Jan 2000 00:00:00 GMT" );
	RQObject.send(null);
	return false;
}

function handle_cat() {
	if(RQObject.readyState != 4) {
		deleteOptions();
	} else {
		if(RQObject.status == 200){
			var str_error = RQObject.responseText.substring(0, 5);
			if(str_error != 'ERROR') {
				var zoekmachines = RQObject.responseText;
				var arr_zoekmachine = zoekmachines.split('|~|');
				for(q=0; q < arr_zoekmachine.length; q++) {
					var arr_info = arr_zoekmachine[q].split('!~!');
					arrTrefwoorden[arr_info[0]] = arr_info[2];
					arrBeschrijvingen[arr_info[0]] = arr_info[3];
					addOption(arr_info[1], arr_info[0]);
					if(q==0) { change_text(arr_info[0]); }
				}
				
			} else {
				// mislukt	
			}
		} else {
			// mislukt	
		}
	}
}

function addOption(text, value)
{
  var newOpt = new Option(text, value);
  var selLength = document.getElementById('slct_machine').length;
  document.getElementById('slct_machine').options[selLength] = newOpt;
}

function deleteOptions()
{ 
   var selLength = document.getElementById('slct_machine').length;
   for(i=0; i < selLength; i++) {
	    document.getElementById('slct_machine').options[i] = null;
   }
}