Oct

28

PBS 24 of x – Creating a JavaScript API

Filed Under Software Development, Computers & Tech on October 28, 2016 | 4 Comments

This post is part 24 of 92 in the series Programming by Stealth

In this instalment we’ll take our JavaScript skill up a level, learning how to write code that is designed to be re-used by ourselves or by others. When you solve a problem that you know you’ll need to solve again, it’s worth putting in a little extra effort to make your code as easy to re-use as possible. You may decide to share that code with others, or you may not, but either way, it’s in your interest to write it using some simple best practices.

Re-usable code without documentation is all but useless, so, we’ll also learn how to create great API documentation as you code. We’ll learn to do this using the free and open source tool JSDoc.

As a worked example, we’ll re-write our link fixer as an easily re-usable API, and while we’re at it we’ll also add in some extra functionality to make its behaviour more customisable, and hence, more useful to more people.

The sample files used in this instalment, as well as some needed libraries, can be downloaded as a ZIP file here. The examples assume you’ll save the files within the zip in a folder named pbs24 in the document root of your local web server.

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Oct

12

PBS 23 of x – Creating Elements with jQuery

Filed Under Computers & Tech, Software Development on October 12, 2016 | 2 Comments

This post is part 23 of 92 in the series Programming by Stealth

So far in this series we have been using jQuery to alter existing HTML elements by changing their attributes or style. In this instalment we take things to the next level, and learn how to use jQuery to create entirely new HTML elements, and inject them into the DOM, and hence, into the web page.

We’ll be working towards our first truly practical assignment in the series – a function that finds all links on a page, and if, and only if, they lead to an external page, alters them to open in a new tab, and appends an icon indicating that fact. In order to work up to that we need to learn five new things:

  1. How to build HTML elements with jQuery
  2. How to inject HTML elements into the DOM
  3. How to loop through each element represented by a jQuery object
  4. How to embed images directly into web pages using Data URLs
  5. How to use the 3rd-party library URI.js to interrogate URLs

There are four examples in this instalment, and a starting-point for the challenge. I’ve gathered them, and the other files they depend on, into a ZIP file which you can download here. It’s assumed that you’ll extract this ZIP file and place the five HTML files and one folder it contains into a folder named pbs23 in your local web server’s htdocs folder. The folder is particularly important because it contains a copy of the URI.js library, and if it’s not in the same folder as pbs23d.html and pbs23-assignment.html, those pages won’t work.

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