AJAX is a set of web development techniques that uses several client-side web technologies to make interactive web apps that can handle user queries in real time. AJAX achieves this by using HTML and CSS for visual rpesentation, XML or JSON for interchange of the data as well as XSLT for manipulation, the Document Object Model (DOM) for dynamic data display, XMLHttpRequest. for asynchronous communication and JavaScript to unify these technologies.

AJAX is the key to allowing content on the web page to be updated instantly, doing so as soon as a visitor performs a particular action. This is different from an HTTP request, where the entire page is reloaded. Because AJAX is heavily reliant on XMLHttpRequest, the first applications to use it would only work with the Internet Explorer browser, but every modern web browser fully supports AJAX.

AMP, or accelerated mobile pages, is an open source framework that allows the web pages to load (and pre-render in Google search) much faster than regular HTML. AMP was developed by Google, Twitter was also involved. The aim of AMP is to give mobile users better and faster experiences. AMP does this because it gives developers the option to simplify both CSS and HTML so that mobile users get a more “lightweight” experience.

Facebook started the trend with its Instant Articles and Google responded with AMP. However, AMP has gained a bigger foothold and today it is a commonly used way to deliver mobile content from search results at a much faster speed – compared to serving a standard page. In fact, AMP has become so prominent and so popular that Google has been pushing to get AMP included in the web standards framework.

You always need to store data in your app – variables are used to store data values. An array is a specific type of variable that can hold multiple values – all under the same variable name. Developers then retrieve a value by referring to it by a text key or indeed an index number in that array.

PHP is the language behind WordPress, and it frequently uses arrays. So when you develop for WordPress or even just use WordPress you are likely to come across arrays – just looking a the core WordPress code will highlight arrays, while you will also see arrays in plugins and themes.

The array() function is used in PHP to create an array. There are three types of arrays in PHP:

• Indexed, where you use a numeric key to access individual values in an array
• Associative, where strings or unique text is used to find the value in an array
• Multidimensional, where a single array in fact contains a number of other arrays

A common way to use an array is to “loop” through the entire set of values in the array and to modify each of these values in some way. As an example, if you have a few pieces of fresh fruit you can store the names of the fruit using a new variable for each fruit, like this:


$myfruits1 = "orange";
$myfruits2 = "peach";
$myfruits3 = "banana";


Alternatively, you can use an array – because using unique variables for each piece of fruit can cause a mess. Programmers would be inclined to use an array that looks like this example:


$myfruits = array("orange", "peach", "banana");


With that array you can use various functions to manipulate the array, performing specific operations on an entire data set all in one go. One example is count() – this function will tell you how many items there are in your array. You can also find a specific value – $fruit[2] will return the word “banana”. Remember that in indexed arrays the first array item is number 0.

Backbone is one of web development frameworks that suits simple single-page applications quite well.  It gives structure to web apps by using models with key-value binding and events, collections with a rich API  and views with declarative event handling. RESTful JSON interface is used here as connection point to your existing API. It follows an MV* pattern in that it implements the MVC design in part. Backbone’s sole core dependency is Underscore.js, and it benefits from a broad ecosystem that makes learning it and using it that bit easier.

Cascading Style Sheets—or CSS for short—is a stylesheet language that tells a webpage how it should  look. It’s used to describe the presentation of a document written in a mark-up language like HTML or XHTML, and it sets out things like colors, fonts and layout. As such, it’s a cornerstone technology of the World Wide Web.

It’s so powerful because it formats content without being a part of it. It effectively modifies the look of content and cascades it across multiple pages of a website, quickly and easily. This is important because it means that the look of hundreds of pages can be altered centrally, in the CSS file, without the need to edit each of those pages manually. It also means that different CSS rules can be applied to fit the size of the device being used to access the page, so with phones and tablets pages can adjust on the fly. This makes any site extremely responsive and makes content more accessible and easier to update. One single HTML page can be offered in a number of different forms to suit different purposes, so the same content can be adapted easily for on-screen reading, print or voice/touch recognition software.

CSS has a simple syntax and every style sheet has a set of rules. They all have a number of selectors and a declaration block. Declaration blocks are comprised of a list of declarations that are book-ended by braces. They have a property, a colon (:), and a value. If there are multiple declarations in a block of CSS code, then a semi-colon (;) needs to be used to separate them.

The selectors in CSS script are used to specify which particular style applies to what portion of the content. Selectors can apply to all elements of a certain type, or to separate groups. CSS supports pseudo-classes in selectors which permits formatting built on data that is external to the page structure.

“Hover” is an example of a pseudo-class. It only identifies content when the on-screen pointer is placed over it. A pseudo-class categorizes page elements using style sheets, such as :link or :visited. A pseudo-element also creates a selection that may be made of partial elements like :first-line or :first-letter. Selectors can be combined in many ways with a CSS program, especially in CSS 2.1, to attain high levels of accuracy and mobility.