//~~~~~~~~~~~
//  Links Page
//~~~~~~~~~~~

//Toggle visibility of div when folder image is clicked and fill links via AJAX
function toggleDiv(img) {
     
     //get category ID and div from image id
     var id = img.id;
     var div = document.getElementById('div' + id);
     
     //show or hide div based on its current state			
     if (div.style.display == 'none'||div.style.display == '') {
          img.src = '/images/links/folderOpen.gif';
          div.style.display = 'block';
          img.alt = 'close'
     }
     else {
          img.src = '/images/links/folderClosed.gif';
          div.style.display = 'none';
          img.alt = 'open'
     }

     //fill div with link data via AJAX call if not already filled
     if (div.innerHTML == '') {
          getLinks(id, div);   
     }
}

// Create AJAX object and get links    
function getLinks(id,div) {    
    httpObject = getHTTPObject();
    if (httpObject != null) {
        httpObject.open("GET", "ajax.php?category="+id, true);
        httpObject.onreadystatechange = function() { 
   	  setOutput(div); 
   	}
        httpObject.send(null); 
    }
}
 
// Load links in div when AJAX data is returned
function setOutput(div) {
    if(httpObject.readyState == 4) {
            div.innerHTML = httpObject.responseText;
    }
}
 

//~~~~~~~~~~~~~~~~~~~~
//   Generic AJAX functions
//~~~~~~~~~~~~~~~~~~~~
var httpObject = null;

// Get the HTTP Object
function getHTTPObject() {
   if (window.ActiveXObject) {
      return new ActiveXObject("Microsoft.XMLHTTP");
   }
   else if (window.XMLHttpRequest) {
      return new XMLHttpRequest();
   }
   else {
      alert("Your browser does not support AJAX.");
      return null;
   }
}