It’s super-common in front-end development to load a lot of content dynamically via AJAX. It’s tempting to rely on jQuery selectors to initialize these elements. We’ve all seen it: a huge chunk of code with twenty anonymous functions, each one a callback to a jQuery .each() method. We like jQuery selector callbacks because they’re convenient–no code is executed unless a match is found. It’s a built-in if-statement! But querying the DOM is an expensive operation which can slow down the loading of your site and drive away users.

If you’re working with Joomla using an HTML5 template and you try and validate your site using the [W3C Markup Validation Service](http://validator.w3.org), you may find yourself hit with the following validation error: *Line 7, Column 44*: **Bad value title for attribute name on element meta: Keyword title is not registered.** Syntax of metadata name: A metadata name listed in the HTML specification or listed in the WHATWG wiki. You can register metadata names on the WHATWG wiki yourself.