What is Child Theme?

A child theme is a theme that inherits the functionality and styling of another theme, called the parent theme. Child themes are the recommended way of modifying an existing theme. The benefits of working off a parent theme means you don’t need to write all the HTML/CSS from scratch. A child theme will automatically use any template files you include, such as sidebar.php or footer.php. But if they are missing, then your child theme will pull the same files from its parent.

Drag and Drop

HTML Drag and Drop interfaces enable applications to use drag and drop features in Firefox and other browsers. For example, with these features, the user can select draggable elements with a mouse, drag the elements to a droppable element, and drop those elements by releasing the mouse button.

How to use jQuery

jQuery is a fast, small, and feature-rich JavaScript library. It makes things like HTML document traversal and manipulation, event handling, animation, and Ajax much simpler with an easy-to-use API that works across a multitude of browsers. jQuery has changed the way that millions of people write JavaScript.

Sessions in PHP

A session is a way to store information (in variables) to be used across multiple pages. Unlike a cookie, the information is not stored on the users computer. The most fundamental way to explain what a sessions is like is to imagine the following scenario: You are working with an application. You open it, make some changes, and then you close it.
That is a session in it’s simplest form.