Ajax is the core technology behind most web applications. It allows a page to make further requests to a web service so data can be presented without a page-refreshing round-trip to the server. The term Ajax is not a technology; instead, it refers to techniques which can load server data…

Understand all the different ways in which you can handle errors in JavaScript — Your apps become more robust as you gain programming experience. Improvements to coding techniques play a large part but you’ll also learn to consider the edge cases. If something can go wrong, it will go wrong: typically when the first user accesses your new system. Some errors are avoidable: A…

Learn how to create great form validations using JavaScript’s native API — Form validation is one of the primary reasons to use client-side JavaScript. It can prevent user entry errors before your app attempts to submit data to the server. But… client-side validation is not a substitute for server-side validation! Always check incoming user data on the server. Not every request will…

Learn what’s coming with the implementation of this phase-3 ECMA proposal — Date handling in JavaScript is ugly. The Date() object has not changed since the first Java-inspired implementation in 1995. Java scrapped it but Date() remained in JavaScript for backward browser compatibility. Issues with the Date() API include: it’s inelegant it only supports UTC and the user’s PC time it doesn’t…

Let’s celebrate Halloween by looking at the darkest corners of Internet — The worst web design patterns are not just for Halloween: they stay with us for years! Some dark patterns are unintentional but most trick you into doing something you didn’t intend. You’ll eventually see though the manipulation but it’s often too late. …

An introduction to the Rollup.js JavaScript bundler — Rollup.js is a Node.js module bundler most often used for client-side JavaScript running in the browser. (You can bundle Node.js scripts but there are fewer reasons to do so). The tool compiles all your JavaScript source files into a single bundle for inclusion in your production web pages. The benefits…

Whoever said internationalization was easy has never tried it. — Like most native-English web developers, I consider internationalization (i18n) too late. English seems ubiquitous, yet it’s spoken by fewer than one in seven people worldwide. It’s the first language of 379 million people but: 917 million speak Mandarin Chinese 460 million speak Spanish, and 341 million speak Hindi. Non-English speakers…

A review of all possible storage options, current, future and obsolete — It’s usually necessary to store user data server side in a database or similar repository. This guarantees persistence and ensures users can access their data from any web-connected browser (presuming your storage system is reliable, of course!) Storing data in the browser becomes a more viable option when: You’re retaining…

Who needs Redux when you can code your own state manager with vanilla JS? — My previous article, Getting Started with IndexedDB for Big Data Storage, demonstrated how to use the browser’s IndexedDB NoSQL database to store data. IndexedDB has good cross-browser support and offers at least 1GB of storage. This article explains how to use IndexedDB to store state in a typical client-side JavaScript…