How to use AJAX as an alternative to iframe - ajax

Question

I'm trying to put together a snappy webapp, utilizing JS, Prototype and AJAX for all my requests once the GUI has loaded. The app is simple: A set of links and a container element to display whatever the links point to, just like an iframe. Here's an approximate HTML snippet:
<a class="ajax" href="/somearticle.html">An article</a>
<a class="ajax" href="/anotherarticle.html">Another article</a>
<a class="ajax" href="/someform.html">Some form</a>
<div id="ajax-container"></div>
The JS that accompanies the above (sorry it's a bit lengthy) looks like this:
document.observe('dom:loaded', function(event) {
ajaxifyLinks(document.documentElement);
ajaxifyForms(document.documentElement);
});
function ajaxifyLinks(container) {
container.select('a.ajax').each(function(link) {
link.observe('click', function(event) {
event.stop();
new Ajax.Updater($('ajax-container'), link.href, {
method: 'get',
onSuccess: function(transport) {
// Make sure new ajax-able elements are ajaxified
ajaxifyLinks(container);
ajaxifyForms(container);
}
});
});
});
}
function ajaxifyForms(container) {
console.debug('Notice me');
container.select('form.ajax').each(function(form) {
form.observe('submit', function(event) {
event.stop();
form.request({
onSuccess: function(transport) {
$('ajax-container').update(transport.responseText);
// Make sure new ajax-able elements are ajaxified
ajaxifyLinks(container);
ajaxifyForms(container);
}
});
});
});
}
When clicking a link, the response is displayed in the container. I'm not using an iframe for the container here, because I want whatever elements are on the page to be able to communicate with each other through JS at some point. Now, there is one big problem and one curious phenomenon:
Problem: If a form is returned and displayed in the container, the JS above tries to apply the same behavior to the form, so that whatever response is received after submitting is displayed in the container. This fails, as the submit event is never caught. Why? Note that all returned form elements have the class="ajax" attribute.
Phenomenon: Notice the console.debug() statement in ajaxifyForms(). I expect it to output to the console once after page load and then every time the container is updated with a form. The truth is that the number of outputs to the console seems to double for each time you click a link pointing to a form. Why?

Answer 1

I found another way to achieve what I wanted. In fact, the code for doing so is smaller and is less error prone. Instead of trying to make sure each link and form element on the page is observed at any given time, I utilize event bubbling and listen only to the document itself. Examining each event that bubbles up to it, I can determine whether it is subject for an AJAX request or not. Here's the new JS:
document.observe('submit', function(event) {
if (event.target.hasClassName('ajax')) {
event.stop();
event.target.request({
onSuccess: function(transport) {
$('ajax-container').update(transport.responseText);
}
});
}
});
document.observe('click', function(event) {
if (event.target.hasClassName('ajax')) {
event.stop();
new Ajax.Updater($('ajax-container'), event.target.href, {
method: 'get'
});
}
});
Works like a charm :)