JavaScript

 

JavaScript Display Possibilities

JavaScript can "display" data in different ways:

• Writing into an HTML element, using innerHTML.
• Writing into the HTML output using document.write().
• Writing into an alert box, using window.alert().
• Writing into the browser console, using console.log().

JavaScript Values

The JavaScript syntax defines two types of values: Fixed values and variable values.

Fixed values are called literals. Variable values are called variables.

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JavaScript Literals

The most important rules for writing fixed values are:

Numbers are written with or without decimals:

JavaScript Variables

In a programming language, variables are used to store data values.

JavaScript uses the var keyword to declare variables.

An equal sign is used to assign values to variables.

In this example, x is defined as a variable. Then, x is assigned (given) the value 6:

Introduction to JavaScript

JavaScript is the programming language of HTML and the Web.

JavaScript is easy to learn.

Why Study JavaScript?

JavaScript is one of the 3 languages all web developers must learn:

   1. HTML to define the content of web pages

   2. CSS to specify the layout of web pages

   3. JavaScript to program the behavior of web pages

JavaScript accepts both double and single quotes:

Bootstrap

 

What is Bootstrap?

• Bootstrap is a free front-end framework for faster and easier web development
• Bootstrap includes HTML and CSS based design templates for typography, forms, buttons, tables, navigation, modals, image carousels and many other, as well as optional JavaScript plugins
• Bootstrap also gives you the ability to easily create responsive designs

What is Responsive Web Design?

Responsive web design is about creating web sites that automatically adjust themselves to look good on all devices, from small phones to large desktops.

Bootstrap 3 vs. Bootstrap 4

Bootstrap 4 is the newest version of Bootstrap; with new components, faster stylesheet, and more responsiveness.

Bootstrap 4 supports the latest, stable releases of all major browsers and platforms. However, Internet Explorer 9 and down are not supported.

Why Use Bootstrap?

Advantages of Bootstrap:

• Easy to use: Anybody with just basic knowledge of HTML and CSS can start using Bootstrap
• Responsive features: Bootstrap's responsive CSS adjusts to phones, tablets, and desktops
• Mobile-first approach: In Bootstrap, mobile-first styles are part of the core framework
• Browser compatibility: Bootstrap 4 is compatible with all modern browsers (Chrome, Firefox, Internet Explorer 10+, Edge, Safari, and Opera)

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Where to Get Bootstrap 4?

There are two ways to start using Bootstrap 4 on your own web site.

You can:

• Include Bootstrap 4 from a CDN
• Download Bootstrap 4 from getbootstrap.com

One advantage of using the Bootstrap 4 CDN:
Many users already have downloaded Bootstrap 4 from MaxCDN when visiting another site. As a result, it will be loaded from cache when they visit your site, which leads to faster loading time. Also, most CDN's will make sure that once a user requests a file from it, it will be served from the server closest to them, which also leads to faster loading time.

jQuery and Popper?
Bootstrap 4 uses jQuery and Popper.js for JavaScript components (like modals, tooltips, popovers, etc). However, if you just use the CSS part of Bootstrap, you don't need them.

Intro to CSS

CSS

What is CSS?

• CSS stands for Cascading Style Sheets
• CSS describes how HTML elements are to be displayed on screen, paper, or in other media
• CSS saves a lot of work. It can control the layout of multiple web pages all at once
• External stylesheets are stored in CSS files

Why Use CSS?

CSS is used to define styles for your web pages, including the

CSS Solved a Big Problem

HTML was NEVER intended to contain tags for formatting a web page!

HTML was created to describe the content of a web page, like:

This is a heading

This is a paragraph.

When tags like , and color attributes were added to the HTML 3.2 specification, it started a nightmare for web developers. Development of large websites, where fonts and color information were added to every single page, became a long and expensive process.

To solve this problem, the World Wide Web Consortium (W3C) created CSS.

CSS removed the style formatting from the HTML page!

If you don't know what HTML is, we suggest that you read our HTML Tutorial.

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CSS Saves a Lot of Work!

The style definitions are normally saved in external .css files.

With an external stylesheet file, you can change the look of an entire website by changing just one file!

design, layout and variations in display for different devices and screen sizes.

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HTML Forms

An HTML form is used to collect user input. The user input can then be sent to a server for processing.

The <form> Element

The HTML <form> element defines a form that is used to collect user input:

<form>
.
form elements
.
</form>

An HTML form contains form elements.

Form elements are different types of input elements, like: text fields, checkboxes, radio buttons, submit buttons, and more.

The <input> Element

The <input> element is the most important form element.

The <input> element is displayed in several ways, depending on the type attribute.

Here are some examples:

Type	Description
<input type="text">	Defines a single-line text input field
<input type="radio">	Defines a radio button (for selecting one of many choices)
<input type="submit">	Defines a submit button (for submitting the form)

Text Fields

<input type="text"> defines a single-line input field for text input.

Example

A form with two text input fields:

<form>
  <label for="fname">First name:</label><br>
  <input type="text" id="fname" name="fname"><br>
  <label for="lname">Last name:</label><br>
  <input type="text" id="lname" name="lname">
</form>

HTML Input Types

Here are the different input types you can use in HTML:

• <input type="button">
• <input type="checkbox">
• <input type="color">
• <input type="date">
• <input type="datetime-local">
• <input type="email">
• <input type="file">
• <input type="hidden">
• <input type="image">
• <input type="month">
• <input type="number">
• <input type="password">
• <input type="radio">
• <input type="range">
• <input type="reset">
• <input type="search">
• <input type="submit">
• <input type="tel">
• <input type="text">
• <input type="time">
• <input type="url">
• <input type="week">

HTML Form Elements

Tag	Description
<form>	Defines an HTML form for user input
<input>	Defines an input control
<textarea>	Defines a multiline input control (text area)
<label>	Defines a label for an <input> element
<fieldset>	Groups related elements in a form
<legend>	Defines a caption for a <fieldset> element
<select>	Defines a drop-down list
<optgroup>	Defines a group of related options in a drop-down list
<option>	Defines an option in a drop-down list
<button>	Defines a clickable button
<datalist>	Specifies a list of pre-defined options for input controls
<output>	Defines the result of a calculation

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Image Map In HTML

Image Map

Image Maps

The HTML <map> tag defines an image map. An image map is an image with clickable areas. The areas are defined with one or more <area> tags.

How Does it Work?

The idea behind an image map is that you should be able to perform different actions depending on where in the image you click.

To create an image map you need an image, and some HTML code that describes the clickable areas.

How to Create Image Map!

HTML Image Tags

Tag	Description
<img>	Defines an image
<map>	Defines an image map
<area>	Defines a clickable area inside an image map
<picture>	Defines a container for multiple image resources

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HTML Tags

HTML tags are the hidden keywords within a web page that define how your web browser must format and display the content. Most tags must have two parts, an opening and a closing part. ... Note that the closing tag has the same text as the opening tag, but has an additional forward-slash ( / ) character.

Basic HTML

Tag	Description
<!DOCTYPE>	Defines the document type
<html>	Defines an HTML document
<head>	Contains metadata/information for the document
<title>	Defines a title for the document
<body>	Defines the document's body
<h1> to <h6>	Defines HTML headings
<p>	Defines a paragraph
<br>	Inserts a single line break
<hr>	Defines a thematic change in the content
<!--...-->	Defines a comment