var http = false;

// Ajax component .. 
if(navigator.appName == "Microsoft Internet Explorer") {
  http = new ActiveXObject("Microsoft.XMLHTTP");
} else {
  http = new XMLHttpRequest();
}

// Change pages ..
function getDynamicContent(url) { 
  //alert(url);
  http.abort();
  http.open("GET", url, true);

  http.onreadystatechange=function() {
    if(http.readyState == 4) { 
      document.getElementById('dbAZcontent').innerHTML = http.responseText;
    }
  }
  http.send(null);
}

function submitBrowseContext(url) {
  var field = 'category';
  for (i=0; i<document.frmBrowse.field.length;i++) {
    if (document.frmBrowse.field[i].checked) {
      field = document.frmBrowse.field[i].value;
    }
  }  

  getDynamicContent(url+"?function=browse&field="+field);
  return;
}


<!-- Thanks D.D. de Kerf -->
function Toggle(id) {
  var imid = 'i' + id;
  var dd = document.getElementById(id);  
  var im = document.getElementById(imid);  
 
  if (dd.style.display == 'none') {          
    dd.style.display = '';
    dd.style.visibility = 'visible';
    im.src = 'images/minus.gif';
  }
  // Collapse the branch if it is visible
  else {          
    dd.style.display = 'none';
    im.src = 'images/plus.gif';
  }
}