/* BASIC AJAX FUNCTION */

function get_XmlHttp() {
	  // Creaza variabila care va contine instanta la XMLHttpRequest, initial cu valoare nula
	  var xmlHttp = null;
	
	  if(window.XMLHttpRequest) {		// Daca browser-ul e Forefox, IE7+, Opera, Safari, ...
		xmlHttp = new XMLHttpRequest();
	  }else if(window.ActiveXObject) {	// Daca browser-ul este Internet Explorer 6 sau 5
		xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
	  }
	  
	  return xmlHttp;
}


function make_request(serverPage, tagID, smethod) {
  var cerere_http =  get_XmlHttp();			// Apeleaza functia pt. crearea instantei la obiectul XMLHttpRequest

  if( smethod!='POST' && smethod!='GET' ) { smethod = "GET"; }
  
  cerere_http.open( smethod, serverPage);			// Defineste datele pt. efectuarea cererii
  cerere_http.send(null);		// Efectuiaza trimiterea datelor

	  // Verifica starea cererii
	  // Daca raspunsul e primit complet, il transfera in eticheta HTML cu id-ul din "tagID"
	  cerere_http.onreadystatechange = function() {
		if (cerere_http.readyState == 4) {
		  document.getElementById(tagID).innerHTML = cerere_http.responseText;
		}
	  }
}


/* Particular functions */

function mm_getByCrit(){
	var mm_media = document.getElementById('media').value;
	var mm_crit  = document.getElementById('criteria').value;
	make_request('request.php?proc=selectMultimedia&act=getByCrit&media='+mm_media+'&crit='+mm_crit, 'mm_value');
}

function mm_getResults(){
	var mm_media  = document.getElementById('media').value;
	var mm_crit   = document.getElementById('criteria').value;
	var mm_value  = document.getElementById('critValue').value;
	if(!mm_value) mm_value='u';
	make_request('request.php?proc=selectMultimedia&act=showResults&media='+mm_media+'&crit='+mm_crit+'&value='+mm_value, 'mm_results');
}