function start() {
   // called by the window.onload event
   setLinkTargets();
   setFormFocus();
}

function setLinkTargets() {
   // needed because XHTML 1.0 Strict does not allow the target-attribute anymore
   if (!document.getElementsByTagName) return;
   var anchors = document.getElementsByTagName("a");
   for (var i=0; i<anchors.length; i++) {
      var anchor = anchors[i];
      if (anchor.getAttribute("href") && anchor.getAttribute("rel") == "external") {
         anchor.target = "_blank";
      }
   }
}

function setFormFocus() {
   // focus on the first form field, if present
   if (document.forms.length) {
      var fields = document.forms[0].elements;
      for (var i=0; i<fields.length; i++) {
         var tag = fields[i].tagName.toLowerCase();
         var type = fields[i].getAttribute('type');
         if ((tag == 'input' && type == 'text') || tag == 'textarea') {
            fields[i].focus();
            return;
         }
      }      
   }
}

function confirmRedirect(msg, url) {
   // redirect after confirmation
   var okay = confirm(msg);
   if (okay) document.location=url;
   return true;
}

function tagMessage(id) {
   // tag message
   var msg = 'Wil je deze roddel markeren voor opname in het lustrumboek?\n(deze optie a.u.b. alleen serieus gebruiken)';
   var okay = confirm(msg);
   if (okay) {
      request = null;
      if (window.XMLHttpRequest) {
         request = new XMLHttpRequest();
      } else if (window.ActiveXObject) {
         request = new ActiveXObject("Microsoft.XMLHTTP");
      }
      if (request == null) {
         alert('Helaas! De benodigde techniek wordt niet ondersteunt door jouw browser.');
      } else {
         request.open('GET', '/tag/'+ id);
         request.onreadystatechange = 
            function() 
            {  if (request.readyState == 4 && request.status == 200) alert('Gelukt!');
            };
         request.send(null);
      }
   }
   return true;
}

function setFormKey() {
   // set form key to prevent spam bots
   document.forms['add'].formkey.value = formKey;
}