JavaScript explained by examples. Widgets and scripts

Summary of the JavaScript programming language
This page is a reference to help in use of our examples and demos.

JavaScript and C: Inheritance and differences

Variables and constants
Variables are dynamic in JavaScript.

• Number
• String
• Array
• Date
• Boolean
• Scope of variables.
• Can we pass variables by reference in JavaScript?

Operators

Array
They are dynamic and have attributes and methods.

• Associative array.
• For each.
• Pitfalls in arrays.
• New methods of Array.
• Comprehension array. How to modify the content of an array of filter it with just one command.

Functions
Defining and calling functions.

• Built-in functions.
• The eval function. This built-in function allows to add variables and functions dynamically.
• The bind method. To solve this issues in callbacks.

Control structures
Loops and conditional expressions.

Regular expression
Processing texts with matching rules.

• Object RegExp.

Events

• Div and mouse. To know the position of the mouse inside a div, what properties?
• Optical illusion. Demonstration: How to change an image when the mouse is pressed down on it.

Objects
In JavaScript, they are dynamic, the structure can grow during a processing.

• This and new, a close relationship. How a function becomes an object.
• Copy, avatar and double. Assigning an object to a variable only adds a reference to the same object. How to make an independent copy?
• Class and inheritance in common JavaScript. It is quite possible to define a constructor and inherit from another class without waiting ES6.

JavaScript and PHP
Sharing variables between PHP and Web pages. Adding variables to that of a form.

Asynchronous JavaScript
How to make JavaScript asynchronous code like that of Analytics from Google?

New features in ECMAScript
And tests of implementation.

• Promise
  Running a code only when the result of a processing is obtained.
• Async/Await
  Examples of use.
• Import and module made simple
  How to import JS modules in the easiest way possible.
  
• JavaScript without callback
  One can avoid the spaghetti code with named functions or promises, particularly when asynchronous functions are chained.
• Converting a callback to a promise
  To turn synchronous an asynchronous function, with await.
• Proxy
  A code simplification tool, proxy allows to separate the bulk of the application of the accessory.
• Map and object: converting nested objects
  Conversions between Map and object when they embed other Map and objects.
  

JavaScript cheat sheet
The essential in one page.

Forms

Creating and using a form.
Principles and form objects in HTML 4 and HTML 5. Adding a button or an image used as button.

List of all form objects in HTML.

Sending and receiving data depending on form objects
Transmitting data to a web page or a script on the server.

• How to pass data to another HTML page. How to pass parameters to a Web page? This is accomplished by a form and a simple script that extracts values from the parameter string.
• GET or POST, what method to choose?
• Frames & forms. How to pass form data between frames of a frameset.

Customizing input text

Checkbox, how to pass the state to another page

Select

Table and query with JSON
Storing a table in a JSON file and accessing its content with a SQL-style query.

HTML Objects

Window
Creating dynamically a window in JavaScript.

• Location. Accessing element of the URL of the page.
• History. Interface to the browser history.
• Dialogs. Interacting with the user, with alert, confirm, prompt.
• Opening a window in JavaScript.
• setTimeout and setInterval. Delay before execution.

Navigator
An object to identify the browser of the user.

Image Map
Links in images.

• Dynamic images. Replacing an image.

Lightbox without framework
To build a lightbox and display text or images in a box, only two CSS descriptors are required. And some JavaScript code is added to dynamically change the contents of the box.

Tab Panel without Framework
A simple Tab Panel for a website or an application in CSS, and to insert another page in the same page with a few lines of JavaScript.

• Tab Panel for HTML application. When the content is already in the page.
• Tab Panel with frames. Second part of the article.

Button switching
How to create a two-states button or textual command.

Scoring article
How to implement a system that allows readers to click on an symbol to give an article a score.

Mysterious picture
Replace with a fade effect a text by a picture, so that the picture is displayed only when needed.

Navigation bar
Accessing the pages of an article splitted into several parts.

Bookmarklets
Adding functions to a webpage with just a link in the page on in the bookmarks. Several examples.

• Bookmarklets for search
  Advanced search function into links.
• Bookmarklets: informations on the page
  Know anything about a webpage.