Next Thursday, the 14th of August I’ll be guest at Stanford University to give a talk about accessibility hacking and Scripting Enabled.

Get all the details on the Stanford Online Accessibility Program Site

This was a question from one of the attendees of my JavaScript course, and here is one solution:

 function getIDsAndClasses(elm,parent){
   var elm = elm || '*';
   if(typeof parent !== 'undefined'){
     if(typeof parent === 'string'){
       var parent = document.getElementById(parent) || document;
     }
   } else {
     var parent = document;
   }
   var elms = parent.getElementsByTagName(elm);
   var ids = [];
   var classesFilter = {};
   var i = elms.length;while(i--){
     if(elms[i].id !== ''){
       ids.push(elms[i].id);
     }
     if(elms[i].className !== ''){
       var singles = elms[i].className.split(' ');
       var j = singles.length;while(j--){
         classesFilter[singles[j]] = singles[j];
       }
     }
   }
   var classes = [];
   for(var i in classesFilter){
    classes[classes.length]=classesFilter[i];
   }
   return {ids:ids,classes:classes}
 }

You can call this method either with no parameters or filter it down by providing an element name and a parent element. The parent element could be a DOM reference or a string, both work.

In any case, the output is an object with a property of ids containing an array of ID names and a property called classes with an array of class names.

The script filters out duplicate classes and gets all applied classes – provided they are space separated.

You can see it in action (in the FireBug console) here: Test getIDsAndClasses

I tried using regex to get the IDs and classes, but that turned out to be a mess in JavaScript.

Any faster way?

I love the YUI loader as it is a great way of including the YUI on the fly. The coolest bits about it is that it gets the YUI components from the CDN and knows the dependencies so I don’t have to. So if I need the YUI for something, I don’t need extra SCRIPT nodes a maintainer has to include, just my SCRIPT. However, what we still need is including the YUI loader itself.

Unless… you use the YAHOO_config listener. This thing is older than both YUI get and YUI Loader and is an object method that gets called every time a YUI component is loaded. So why not load the YUI Loader using this?

One problem is that the YUI Loader doesn’t call the config listener saying it is a loader, but saying it is the get utility. Another issue is that it does not work to execute the Loader immediately after it called itself “get”. The workaround is to use a timeout.

Wrap all of that inside the YAHOO_config object and you’ll conjure the YUI out of thin air. The following example loads YUI Dom, YUI Event and alerts “done” once all is ready. Check it out here

YAHOO_config = function(){
var s = document.createElement('script');
s.setAttribute('type','text/javascript');
s.setAttribute('src','http://yui.yahooapis.com/2.5.2/'+
'build/yuiloader/yuiloader-beta-min.js');
document.getElementsByTagName('head')[0].appendChild(s);
return{
listener:function(o){
if(o.name === 'get'){
window.setTimeout(YAHOO_config.ready,1);
}
},
ready:function(){
var loader = new YAHOO.util.YUILoader();
var dependencies = ['yahoo','dom','event'];
loader.require(dependencies);
loader.loadOptional = true;
loader.insert({
onSuccess:function(){
console.log('done!');
}
});
}
};
}();

Thanks to Alex Liu to get the setTimeout trick.

During the course I am currently giving in Sunnyvale on basics of the DOM and progressive enhancement I asked the attendees which methods seem to be missing in the native DOM implementation and this is what we came up with:

• createLink(url,text) – a shortcut method to create a link with a text node inside – something you constantly have to do when creating interfaces
• insertAfter(newNode,oldNode) – there is an insertBefore, but no insertAfter
• removeNode(node) – the native removeChild is convoluted
• textElement(elementName,text) – it seems not necessary to create an Element, then create a text node and apply it, this could be one step
• addScript(url) – to lazy-load JavaScripts
• normalizeNode(node) – to remove those pesky line-breaks that interfere with nextSibling or previousSibling
• getText(node) – retrieving the text content of a node that is either a text or an element node
• setText(node,text) – setting the text regardless of node type

I asked the attendees to come up with a method each and to present them, here’s what we got:

jukuhelpers = function(){
function createLink(url,text,cssClass){
var link =  document.createElement('a');
if (typeof url = 'string'){
link.setAttribute('href', url);
}
if (typeof text = ‘string’){
link.appendChild(document.createTextNode(text));
}
if (typeof cssClass = 'string'){
link.className = cssClass;
}
return link;
}
function insertAfter(newNode,oldNode){
oldNode.nextSibling
? oldNode.parentNode.insertBefore(newNode, oldNode.nextSibling)
: oldNode.parentNode.appendChild(newNode);
}
function removeNode(node){
if (node) {
node.parentNode.removeChild(node);
}
}
function textElement(elementName,text){
if (typeof text = ‘string’){
var txtElement = document.createElement(elementName);
var txtNode = document.createTextNode(text);
txtElement.appendChild(txtNode);
}
return txtElement;
}
function addScript(url){
var s = document.createElement(‘script’);
s.setAttribute(‘type’, ‘text/javascript’);
s.setAttribute(‘src’, url);
var head = document.getElementsByTagName(‘head’)[0];
head.appendChild(s);
}
function getText(node){
var txt;
if (node && node.nodeType = 1) {
if (node.hasChildNodes()) {
txt = node.firstChild.nodeValue;
}
}
if (node && node.nodeType = 3) {
txt = node.nodeValue;
}
return txt;
}
function setText(node,text){
if (node && node.nodeType = 1) {
if (node.hasChildNodes()) {
node.firstChild.nodeValue = text;
}
else {
node.appendChild(document.createTextNode(text));
}
}
if (node && node.nodeType = 3) {
node.nodeValue = text;
}
}
function normalizeNode(node){
if(node.hasChildNodes){
var spaceTest = /^s+$/;
var children = node.childNodes;
for(var i=0;children[i];i++){
if(children[i].nodeType === 3){
if(spaceTest.test(children[i].nodeValue)){
children[i].parentNode.removeChild(children[i]);
}
}
}
}
}
return{
createLink:createLink,
insertAfter:insertAfter,
removeNode:removeNode,
textElement:textElement,
addScript:addScript,
getText:getText,
setText:setText,
normalizeNode:normalizeNode
}
}();

You can get the jukuhelpers.js file if you want to use it yourself.

Anything else that is missing or any bugs in this?

My esteemed colleage Klaus Komenda seems to spend as much time as I do writing cool stuff for the masses, but somehow he doesn’t crop up in a lot of to-read lists. For shame, I say, pulling up my trousers until they reach my armpits (yes, I watched Simpsons) and I point you, esteemed reader to a series of articles explaining the YUI from ground up entitled Agent YUI:

• Get a lot of easy-to-understand YUI tutorials here

Yes, I am also taken with them as I like Bond a lot.