var xmlHttp ;

function GetXmlHttpObject()

{

xmlHttp=null;

try

  {

  // Firefox, Opera 8.0+, Safari

  xmlHttp=new XMLHttpRequest();

  }

catch (e)

  {

  // Internet Explorer

  try

    {

    xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");

    }

  catch (e)

    {

    xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");

    }

  }

return xmlHttp;

}

function stateChanged_cat0() {
   if (xmlHttp.readyState != 4) {
      return ;
   }
   
   obj_cat1 = document.getElementById("categories1") ;
   obj_cat1.options.length = 0 ;
   obj_cat2.options.length = 0 ;
   
   my_str = xmlHttp.responseText ; 
   arrayOfStrings = my_str.split("~") ;
   num_of_sub_categories = arrayOfStrings.length ;	
   for (i_str = 0; i_str < num_of_sub_categories; i_str++) {
      s_option_str = arrayOfStrings[i_str] ;
	  a_option_data = s_option_str.split("^") ; 
	  cat_id = a_option_data[1] ;
	  cat_name = a_option_data[0] ;
	  obj_cat1.options[i_str] = new Option(cat_id, cat_name) ;
   }
} // function stateChanged_cat0

function categoty0_change() {
   obj_cat0 = document.getElementById("categories0") ;
   obj_cat1 = document.getElementById("categories1") ;
   obj_cat2 = document.getElementById("categories2") ;
   if (obj_cat0.selectedIndex == 0) {
      obj_cat1.options.length = 0 ;
      obj_cat2.options.length = 0 ; 
      return ;
   }

   category_id = obj_cat0.options[obj_cat0.selectedIndex].value ;
   url = "http://www.combooks.co.il/Combooks_IL2/get_category_children.php?category_id=" + category_id ;
   
   xmlHttp=GetXmlHttpObject();
   if (xmlHttp==null) {
      alert ("Your browser does not support AJAX!");
      return;
   }	
   
   xmlHttp.onreadystatechange = stateChanged_cat0 ;
   xmlHttp.open("GET", url, true);
   xmlHttp.send(null);	
} // function categoty0_change()

function stateChanged_cat1() {
   if (xmlHttp.readyState != 4) {
      return ;
   }
   
   obj_cat2 = document.getElementById("categories2") ;
   obj_cat2.options.length = 0 ;
   
   my_str = xmlHttp.responseText ; 
   arrayOfStrings = my_str.split("~") ;
   num_of_sub_categories = arrayOfStrings.length ;	
   for (i_str = 0; i_str < num_of_sub_categories; i_str++) {
      s_option_str = arrayOfStrings[i_str] ;
	  a_option_data = s_option_str.split("^") ; 
	  cat_id = a_option_data[1] ;
	  cat_name = a_option_data[0] ;
	  obj_cat2.options[i_str] = new Option(cat_id, cat_name) ;
   }
} // function stateChanged_cat1

function categoty1_change() {
   obj_cat1 = document.getElementById("categories1") ;
   obj_cat2 = document.getElementById("categories2") ;
   if (obj_cat1.selectedIndex == 0) {
      obj_cat2.options.length = 0 ; 
      return ;
   }

   category_id = obj_cat1.options[obj_cat1.selectedIndex].value ;
   url = "http://www.combooks.co.il/Combooks_IL2/get_category_children.php?category_id=" + category_id ;
   
   xmlHttp=GetXmlHttpObject();
   if (xmlHttp==null) {
      alert ("Your browser does not support AJAX!");
      return;
   }	
   
   xmlHttp.onreadystatechange = stateChanged_cat1 ;
   xmlHttp.open("GET", url, true);
   xmlHttp.send(null);	
} // function categoty1_change()

function search_type() {
   obj_year = document.getElementById("tr_years1") ;
   obj_cat01 = document.getElementById("tr_categories01") ;
   obj_cat02 = document.getElementById("tr_categories02") ;
   obj_cat11 = document.getElementById("tr_categories11") ;
   obj_cat12 = document.getElementById("tr_categories12") ;
   obj_cat21 = document.getElementById("tr_categories21") ;
   obj_cat22 = document.getElementById("tr_categories22") ;
   obj_url = document.getElementById("a_search_type") ;
   
   if (obj_year.style.display == 'none') {   	
      display_type = "block" ;
      url_text = "Regular Search"	;
   } else {
   	  display_type = "none" ;
   	  url_text = "Advanced Search" ;
   }
   
   obj_year.style.display = display_type ;
   obj_cat01.style.display = display_type ;
   obj_cat02.style.display = display_type ;
   obj_cat11.style.display = display_type ;
   obj_cat12.style.display = display_type ;
   obj_cat21.style.display = display_type ;
   obj_cat22.style.display = display_type ;
   obj_url.innerHTML = url_text ;
} // function search_type()

function submit_forms(form_id) {
   document.getElementById(form_id).submit() ;   	
}