jQuery setTimeout() Function Examples

The JavaScript setTimeout function calls a function or executes a code snippet after a specified delay (in milliseconds). This might be useful if, for example, you wished to display a popup after a visitor has been browsing your page for a certain amount of time, or you want a short delay before removing a hover effect from an element (in case the user accidentally moused out).
Basic setTimeout Example
To demonstrate the concept, the following demo displays a popup, two seconds after the button is clicked.

See the Pen CSS3 animation effects for Magnific Popup by SitePoint (@SitePoint) on CodePen.

From the MDN documentation, the syntax for setTimeout is as follows:
[code language=”js"]
var timeoutID = window.setTimeout(func, [delay, param1, param2, …]);
var timeoutID = window.setTimeout(code, [delay]);

timeoutID is a numerical id, which can be used in conjunction with clearTimeout() to cancel the timer.
func is the function to be executed.
code (in the alternate syntax) is a string of code to be executed.
delay is the number of milliseconds by which the function call should be delayed. If omitted, this defaults to 0.

setTimeout vs window.setTimeout
You’ll notice that the syntax above uses window.setTimeout. Why is this?
Well, setTimeout and window.setTimeout are essentially the same, the only difference being that in the second statement we are referencing the setTimeout method as a property of the global window object.
In my opinion this adds complexity, for little or no benefit—if you’ve defined an alternative setTimeout method which would be found and returned in priority in the scope chain, then you’ve probably got bigger issues.
For the purposes of this tutorial, I’ll omit window, but ultimately which syntax you chose is up to you.
The post jQuery setTimeout() Function Examples appeared first on SitePoint.

Link: https://www.sitepoint.com/jquery-settimeout-function-examples/

10 Essential Sublime Text Plugins for JavaScript Developers

In this article, I’ll outline ten must-have Sublime Text plugins for JavaScript developers, each of which can improve your workflow and make you more productive.
Sublime Text is a great application for just about any developer to have in their toolbox. It’s a cross-platform, highly customizable, advanced text editor that sits nicely between full featured IDEs (which are notoriously resource hungry) and command line editors such Vim or Emacs (which have steep learning curves).
In recent years, Sublime has gained welcome competition from both Visual Studio Code and Atom, but Sublime Text still holds its own by being indisputably faster, being able to open larger files faster than the others.
One of the things that makes Sublime so great is its extensible plugin architecture. This makes it easy for developers to extend Sublime’s core functionality with new features like code completion, or the embedding of remote API documentation. Sublime Text doesn’t come with plugins enabled out of the box: they’re typically installed through a 3rd-party package manager simply called Package Control. To install Package Control in Sublime Text, please follow the installation guide on their website.
So let’s get to it!
1. Babel
Of course, the first one on my list is the Babel plugin. This plugin adds proper syntax highlighting to your ES6/2015 and React JSX code. After installing the plugin, the first thing you should do is set it as the default syntax for all of your JavaScript and TypeScript file types.
If you haven’t yet discovered the joy of Babel, I highly suggest it. It allows you to compile ES6/ES7/ESNext, JSX, and TypeScript code down to ES5 for full browser support. It integrates well with all popular build tools and the CLI. Obviously, it doesn’t support legacy browsers, but you can follow the tips on their caveats page if you need to support IE10 and below.

2. SublimeLinter
Next up is SublimeLinter, which provides amazing ESLint and JSHint integration into Sublime. A linter will look over your code and verify it has proper styling and proper syntax based on a configuration file that can be checked in with your source code. No matter if you’re a beginner or have been programming for most of your life: in JavaScript, a linter is a must have. Check out the ESLint or JSHint about pages to see what they can do for you. Depending on which you chose for your project, you’ll also need the supporting packages of SublimeLinter-eslint or SublimeLInter-jshint.
In order for either of these to work, you must include a linter either into your project dependencies or install it globally:
npm install –save-dev eslint

If you’re unsure how to use npm, check out our tutorial on getting started with Node Package Manager.

If you’ve installed and configured it correctly, you should see the changes when you open or save a JavaScript file. The plugin is incredibly configurable and can be made to report in a number of ways that might be better for your workflow. By default, the description of the errors will be reported in the status bar at the bottom of the editor.
Continue reading %10 Essential Sublime Text Plugins for JavaScript Developers%

Link: https://www.sitepoint.com/essential-sublime-text-javascript-plugins/

AngularJS and Angular 2+: a Detailed Comparison

This article compares the major differences between the the original AngularJS and Angular 2+. If you’re currently stuck with an AngularJS project and not sure whether you should make the jump, this article should help you get started.
In recent years, we’ve seen Angular grow tremendously as a framework and as a platform for developing single page applications (SPAs) and progressive web apps (PWAs). AngularJS was built on top of the idea that declarative programming should be used for building the views. This required decoupling the DOM manipulation from the business logic of the application and the approach had many benefits on its own.
However, AngularJS had many shortcoming in terms of performance and how things worked under the hood. Hence, the development team spent a year rewriting the code from scratch and finally released Angular 2 in late 2016. Most developers felt that Angular 2 was a different platform that had very little resemblance to the original AngularJS.
So let’s compare and contrast AngularJS and Angular 2+.
Frameworks in AngularJS and Angular 2
AngularJS follows the traditional MVC architecture that comprises a model, a view and a controller.

Controller: the controller represents how user interactions are handled and binds both the model and the view.
Views: the view represents the presentation layer and the actual UI.
Model: the model is an abstract representation of your data.

Some developers are of the opinion that AngularJS follows MVVM pattern that replaces the Controller with a View-Model. A View-Model is a JavaScript function that’s similar to that of the controller. What makes it special is that it synchronizes the data between a view and a model. The changes made to a UI element automatically propagate to the model and vice versa.
The following diagram shows how various AngularJS pieces are connected together.

You can read more about AngularJS’s architecture on the official documentation page.
Angular, on the other, hand has a component-based architecture. Every Angular application has at least one component known as the root component. Each component has an associated class that’s responsible for handling the business logic and a template that represents the view layer. Multiple, closely related components can be stacked together to create a module and each module forms a functional unit on its own.

As you can see in the figure, the component is bound to the template. Components are composed using TypeScript classes and templates are attached to them using @Component annotations. Services can be injected into a component using Angular’s dependency injection subsystem. The concept of modules in Angular is drastically different from that of the AngularJS modules. An NgModule is a container for defining a functional unit. An NgModule can comprise components, services and other functions. The modular unit can then be imported and used with other modules.
All the Angular concepts are better explained at Angular.io.
Templates in AngularJS and Angular 2
In AngularJS the template is written using HTML. To make it dynamic, you can add AngularJS-specific code such as attributes, markups, filters and form controls. In addition, it supports the two-way data binding technique mentioned earlier. The following code snippet demonstrates the use of directives and double curly brackets within the template:

<!– Body tag augmented with ngController directive –>
<body ng-controller=”MyController">
<inpu#t ng-model="foo" value="bar">
<!– Button tag with ngClick directive –>
<!– Curly bracket is a template binding syntax –>
button ng-click="changeFoo()"></button>
<script src="angular.js"></script>

In Angular, AngularJS’s template structure was reworked and lots of new features were added to the templates. The primary difference was that each component had a template attached to it. All the HTML elements except <html>, <body>, <base>, and <script> work within the template. Apart from that, there are features such as template binding, template interpolation, template statements, property binding, event binding and two-way binding. Built-in attribute directives like NgClass, NgStyle and NgModel and built-in structural directives such as NgIf, NgForOf, NgSwitch are also part of the template.
Continue reading %AngularJS and Angular 2+: a Detailed Comparison%

Link: https://www.sitepoint.com/angularjs-vs-angular/

How to Build a File Upload Form with Express and Dropzone.js

Let’s face it, nobody likes forms. Developers don’t like building them, designers don’t particularly enjoy styling them and users certainly don’t like filling them in.
Of all the components that can make up a form, the file control could just be the most frustrating of the lot. A real pain to style, clunky and awkward to use and uploading a file will slow down the submission process of any form.
That’s why a plugin to enhance them is always worth a look, and DropzoneJS is just one such option. It will make your file upload controls look better, make them more user-friendly and by using AJAX to upload the file in the background, at the very least make the process seem quicker. It also makes it easier to validate files before they even reach your server, providing near-instananeous feedback to the user.
We’re going to take a look at DropzoneJS in some detail; show how to implement it and look at some of the ways in which it can be tweaked and customized. We’ll also implement a simple server-side upload mechanism using Node.js.
As ever, you can find the code for this tutorial on our GitHub repository.
Introducing DropzoneJS
As the name implies, DropzoneJS allows users to upload files using drag n’ drop. Whilst the usability benefits could justifiably be debated, it’s an increasingly common approach and one which is in tune with the way a lot of people work with files on their desktop. It’s also pretty well supported across major browsers.
DropzoneJS isn’t simply a drag n’drop based widget, however; clicking the widget launches the more conventional file chooser dialog approach.
Here’s an animation of the widget in action:

Alternatively, take a look at this, most minimal of examples.
You can use DropzoneJS for any type of file, though the nice little thumbnail effect makes it ideally suited to uploading images in particular.
To summarize some of the plugin’s features and characteristics:

Can be used with or without jQuery
Drag and drop support
Generates thumbnail images
Supports multiple uploads, optionally in parallel
Includes a progress bar
Fully themeable
Extensible file validation support
Available as an AMD module or RequireJS module
It comes in at around 33Kb when minified

Browser Support
Taken from the official documentation, browser support is as follows:

Chrome 7+
Firefox 4+
IE 10+
Opera 12+ (Version 12 for MacOS is disabled because their API is buggy)
Safari 6+

There are a couple of ways to handle fallbacks for when the plugin isn’t fully supported, which we’ll look at later.
The simplest way to install DropzoneJS is via Bower:
bower install dropzone

Alternatively you can grab it from Github, or simply download the standalone JavaScript file — though bear in mind you’ll also need the basic styles, also available in the Github repo.
There are also third-party packages providing support for ReactJS and implementing the widget as an Angular directive.
First Steps
If you’ve used the Bower or download method, make sure you include both the main JS file and the styles (or include them into your application’s stylesheet), e.g:

Link: https://www.sitepoint.com/file-upload-form-express-dropzone-js/

An Introduction to Functional JavaScript

You’ve heard that JavaScript is a functional language, or at least that it’s capable of supporting functional programming. But what is functional programming? And for that matter, if you’re going to start comparing programming paradigms in general, how is a functional approach different from the JavaScript that you’ve always written?
Well, the good news is that JavaScript isn’t picky when it comes to paradigms. You can mix your imperative, object-oriented, prototypal, and functional code as you see fit, and still get the job done. But the bad news is what that means for your code. JavaScript can support a wide range of programming styles simultaneously within the same codebase, so it’s up to you to make the right choices for maintainability, readability, and performance.
Functional JavaScript doesn’t have to take over an entire project in order to add value. Learning a little about the functional approach can help guide some of the decisions you make as you build your projects, regardless of the way you prefer to structure your code. Learning some functional patterns and techniques can put you well on your way to writing cleaner and more elegant JavaScript regardless of your preferred approach.
Imperative JavaScript
JavaScript first gained popularity as an in-browser language, used primarily for adding simple hover and click effects to elements on a web page. For years, that’s most of what people knew about it, and that contributed to the bad reputation JavaScript earned early on.
As developers struggled to match the flexibility of JavaScript against the intricacy of the browser document object model (DOM), actual JavaScript code often looked something like this in the real world:
[code language=”js"]
var result;
function getText() {
var someText = prompt("Give me something to capitalize");
alert(result.join(" "));
function capWords(input) {
var counter;
var inputArray = input.split(" ");
var transformed = "";
result = [];
for (counter = 0; counter < inputArray.length; counter++) { transformed = [ inputArray[counter].charAt(0).toUpperCase(), inputArray[counter].substring(1) ].join(""); result.push(transformed); } }; document.getElementById("main_button").onclick = getText; [/code] So many things are going on in this little snippet of code. Variables are being defined on the global scope. Values are being passed around and modified by functions. DOM methods are being mixed with native JavaScript. The function names are not very descriptive, and that’s due in part to the fact that the whole thing relies on a context that may or may not exist. But if you happened to run this in a browser inside an HTML document that defined a <button id="main_button">, you might get prompted for some text to work with, and then see the an alert with first letter of each of the words in that text capitalized.
Imperative code like this is written to be read and executed from top to bottom (give or take a little variable hoisting). But there are some improvements we could make to clean it up and make it more readable by taking advantage of JavaScript’s object-oriented nature.
Continue reading %An Introduction to Functional JavaScript%

Link: https://www.sitepoint.com/introduction-functional-javascript/

6 jQuery Form Wizard Plugins

A jQuery Form Wizard is a jQuery plugin that assists with the creation of forms with some sort of form flow (without refreshing your page). For example, if you had a large form for entering user data, you could use a form wizard to divide it into a series of related steps. This has the advantage of not overwhelming users with a really long form and also giving them some indication of their progress as they enter their information.
In this post we list 6 of our favorite jQuery form wizards, examine their different features and finally look at a couple of paid options, as well as how to create your own. This isn’t intended to be an exhaustive list, but if you are looking for a jQuery form wizard, then hopefully this will point you in the right direction.

This popular post was updated on 30.08.2017. Broken / abandoned plugins were removed from the list and new plugins were added to reflect features people were asking for in the comments.

1. jQuery Steps
jQuery Steps is a smart UI component which allows you to easily create wizard-like interfaces. This plugin groups content into sections for a more structured and orderly page view. It has a plethora of features, such as async content loading, state persistence (it saves your input between steps) and transition effects between sections. It can be installed via NuGet or bower and has a well-documented and feature-rich API.

Homepage | GitHub | Demo
2. jQuery Smart Wizard
Smart Wizard is a flexible and heavily customizable jQuery step wizard plugin with Bootstrap support. It is easy to implement and gives a neat and stylish interface for your forms, checkout screen, registration steps etc. Its features include theme support (with various themes included), URL navigation and step selection and the ability to dynamically hide or disable steps. It can be installed via npm, bower or composer and has a well-documented and feature-rich API.

Homepage | GitHub | Demo
3. formToWizard
This lightweight plugin turns any webform into multi-step wizard with jQuery, whereby every form

is turned into a separate step with forward and back buttons. It doesn’t have nearly as many features as the previous two plugins, but does integrate with the jQuery validation plugin to provide validation functionality. It is a single file (so you can just grab it off GitHub and go) and if JavaScript is unavailable, it degrades gracefully.

GitHub | Demo
Continue reading %6 jQuery Form Wizard Plugins%

Link: https://www.sitepoint.com/jquery-form-wizard-plugins/

Your Site without JavaScript

This post was originally published on calibreapp.com and reposted here with the author’s permission. If you’re interested in taking Calibre for a spin, you can start a free 14-day trial today.
There are plenty of reasons why the presence of JavaScript (what it does, how it works, and how heavy it is) needs to be considered a little more thoughtfully.
Web traffic today is made up of more than 50% mobile devices, of these devices, many operate under extremely volatile network connections—loading scripts alone in less than 10 seconds is nigh on impossible in many situations.
If you’re working on a single page app, with no reasonable content-only fallbacks, this can be far more damaging than you may think—users will be watching a white screen, with partial content, for a long time.

According to Google’s DoubleClick, when comparing sites that load in 5 seconds to sites that load in 19 seconds, the faster sites had 70% longer average session lengths, 35% lower bounce rates and 25% higher ad viewability than their slower counterparts.

Performance is important, there’s no doubting that, but what common negative impacts does JavaScript have on our sites? How are we currently evaluating performance?
Let’s Have a Brief (but Constructive) Look at the Cost of JavaScript
When commonly auditing the performance impacts of JavaScript, we look at:

The number of render-blocking scripts present on the page
How long scripts take to download, and the amount of data transferred

But what we’re often missing is what happens thereafter…
Once the device has downloaded the scripts, they must be parsed, converted to bytecode, compiled and then executed.
Parse and compile time are two reasons why the same site that works great on your $3000 MacBook, feels kind of janky on a 2-year-old smartphone.

The above graphic compares Chrome parse/compile times on a regular desktop browser, verses a low power mobile device. This graphic is taken from Addy Osmani’s excellent article titled “JavaScript Start-up Performance".

Let’s say, as an experiment, that we removed all scripts to establish a performance baseline, to answer the question "Just how fast could this be?".
Calibre exists to make it trivial for teams to have better visibility to more areas of performance and user-experience, so in the spirit of that, you can now run a direct comparison of your site with, or without JS—as a Test profile.

💥Now you’re testing with and without JavaScript
I enabled the ability to disable scripts, and run a few test runs against popular global news sites, both with, and without JavaScript.
Continue reading %Your Site without JavaScript%

Link: https://www.sitepoint.com/calibre-your-site-without-javascript/

How to Create a QR Code Reader for Your Mobile Website

The barcode and QR code have modernized our shopping and searching experience. Customers carrying smartphones can now pick up a product anywhere in the world, scan its barcode or its QR code using one of the many free phone apps and find out its lowest price as well as where it can be bought.

Companies like Walmart and Amazon have embraced this technique to draw customers to their online and offline stores using their phone app. Other companies like Fedex and UPS allow customers to scan the codes on packages using a phone app, instead of needing to manually type in long lists of characters.
If the users of your mobile website have a need to type in long codes like activation codes or they like to look up specific products on your website based on a model number printed in a magazine or advertisement, then you too can take advantage of QR codes to eliminate the frustration of tiny keyboards and spare them the need to double check for errors.
QR Code Scanning with your Mobile Website
You don’t need a native phone app to scan QR codes —it’s quite simple to create your own QR code reader. Your website running on a smartphone equipped with a camera and running a little JavaScript can do the same trick.
Here is a demo of a text field with an in-built QR button. In addition to being able to type text into the field, users can also click a button to activate the camera.

Browser Requirements:
Your users need to be on an iPhone running iOS 6 or higher or an Android phone running Android 3.0 or higher. Other devices have not been tested.

See the Pen Bare QR reader demo by SitePoint (@SitePoint) on CodePen.

If you are on a supported device, go ahead and click it. Depending on your phone, it will either launch the camera immediately or ask you whether to open the camera or browse your photo library. On unsupported devices, the browser will open up a regular file explorer window.
If you don’t have a QR code handy to scan, here is one that shows the first 8 digits of Pi.

Creating the QR Code Reader
The magic starts with the file upload element. We spruce it up with an accept attribute which tells the browser that we only want images and we give it a capture attribute which means we want the input to be captured now, as opposed to uploading an old picture from the phone’s memory.

Link: https://www.sitepoint.com/create-qr-code-reader-mobile-website/

JavaScript Design Patterns: The Observer Pattern

In JavaScript, there is a problem that comes up often. You need a way to update parts of a page in response to certain events, with the data these provide. Say, for example, user input that you then project into one or many components. This leads into a lot of push-and-pull in the code to keep everything in sync.
This is where the observer design pattern can help — it enables one-to-many data binding between elements. This one-way data binding can be event driven. With this pattern, you can build reusable code that solves for your specific needs.
In this article, I’d like to explore the observer design pattern. It will help you solve a common problem you see in client-side scripting. That is one-to-many, one-way, and event-driven data binding. It is a problem that comes up often when you have many elements that must be in sync.
I’ll use ECMAScript 6 to illustrate the pattern. Yes, there will be classes, arrow functions, and constants. Feel free to explore these topics on your own if you are not already familiar. I’ll use parts of ES6 that introduce syntactic sugar only, so it is portable with ES5 if need be.
And I’ll use Test-Driven-Development (TDD) to work on the pattern. This way you have a way knowing how each component is useful.
The new language features in ES6 make for some succinct code. So, let’s get started.
The Event Observer
A high-level view of the pattern looks like this:

├── subscribe: adds new observable events

├── unsubscribe: removes observable events
└── broadcast: executes all events with bound data

After I flesh out the observer pattern I’ll add a word count that uses it. The word count component will take this observer and bring it all together.
To initialize the EventObserver do:
class EventObserver {
constructor() {
this.observers = [];

Start with an empty list of observed events, and do this for every new instance. From now on, let’s add more methods inside EventObserver to flesh out the design pattern.
The Subscribe Method
To add new events do:
subscribe(fn) {

Grab the list of observed events and push a new item to the array. The list of events is a list of callback functions.
One way to test this method in plain JavaScript is as follows:
// Arrange
const observer = new EventObserver();
const fn = () => {};

// Act

// Assert
assert.strictEqual(observer.observers.length, 1);

I use Node assertions to test this component in Node. The exact same assertions exist as Chai assertions too.
Note the list of observed events consists of humble callbacks. We then check the length of the list and assert that the callback is on the list.
The Unsubscribe Method
To remove events do:
unsubscribe(fn) {
this.observers = this.observers.filter((subscriber) => subscriber !== fn);

Continue reading %JavaScript Design Patterns: The Observer Pattern%

Link: https://www.sitepoint.com/javascript-design-patterns-observer-pattern/

Grab Our Free Printable Functional JavaScript Cheat Sheet

Functional programming (FP) has become a hot topic in the JavaScript community. It’s being touted as a great way of building scalable and maintainable applications and we’re staring to see many of its core principles incorporated into libraries and frameworks — for example stateless functional components in React.
Continue reading %Grab Our Free Printable Functional JavaScript Cheat Sheet%

Link: https://www.sitepoint.com/grab-free-printable-functional-javascript-cheat-sheet/