Many Rich Internet Applications (RIAs) manipulate HTML after the page has already loaded by using technologies like DHTML and AJAX.
For example, after clicking a button, your Web page may display a new section of content. This scenario is supported, allowing you to define dynamic mboxes through its mboxDefine() and mboxUpdate() functions.
For example, if you want to serve content when an HTML node called "dynamicElement" appears on the page:
mboxDefine() does not actually serve content so it should be followed with mboxUpdate().
Like mboxCreate, it takes in the mbox name and any number of parameters.
This allows the page to update content dynamically after the initial page load.
When using dynamic mboxes, delivering offers that include document.write cause the page where the dynamic mbox is located to appear blank because the document.write function is invoked after the DOM has loaded. Note also that plug-ins using offers with document.write should never be used on sites employing dynamic mboxes.