web chapter 1

Cascading Style Sheets (CSS)

1- Cascading Style Sheets (CSS) are used to specify the presentation, or styling, of elements on a web page (e.g., fonts, spacing, sizes, colors, positioning). 2- CSS was designed to style portable web pages independently of their content and structure. By separating page styling from page content and structure, you can easily change the look and feel of the pages on an entire website, or a portion of a website, simply by swapping out one style sheet for another. (CSS3 is the current version of CSS under development) 3- Although HTML5 provides some capabilities for controlling a document's presentation, it's better not to mix presentation with content.

Web Browsers and Web-Browser Portability

1- Ensuring a consistent look and feel on client-side browsers is one of the great challenges of developing web-based applications. 2- Vendors add features to each new version that sometimes result in cross-platform incompatibility issues. 3- It's difficult to develop web pages that render correctly on all versions of each browser. 4- Although browsers share a common set of features, each browser might render pages differently.

Moore's Law

1- Every year or two, the capacities of computers have approximately doubled inexpensively. 2- Moore's Law and related observations apply especially to the amount of memory that computers have for programs, the amount of secondary storage (such as disk storage) they have to hold programs and data over longer periods of time, and their processor speeds—the speeds at which computers execute their programs (i.e., do their work).

HTML5

1- HTML (HyperText Markup Language) is a special type of computer language called a markup language designed to specify the content and structure of web pages (also called documents) in a portable manner. 2-HTML enables you to create content that will render appropriately across the extraordinary range of devices connected to the Internet—including smartphones, tablet computers, notebook computers, desktop computers, special-purpose devices such as large-screen displays at concert arenas and sports stadiums, and more.

JavaScript

1- JavaScript helps you build dynamic web pages (i.e., pages that can be modified "on the fly" in response to events, such as user input, time changes and more) and computer applications. It enables you to do the client-side programming of web applications. 2- JavaScript was created by Netscape. Both Netscape and Microsoft have been instrumental in the standardization of JavaScript by ECMA International (formerly the European Computer Manufacturers Association) as ECMAScript. 3- ECMAScript 5, the latest version of the standard, corresponds to the version of JavaScript we use in this book. 4- JavaScript is a portable scripting language. Programs written in JavaScript can run in web browsers across a wide range of devices.

XHTML

A "stricter" version of HTML called XHTML (Extensible HyperText Markup Language), which is based on XML (eXtensible Markup Language), is still used frequently today.

Packet Switching

The network operated with a technique called packet switching, in which digital data was sent in small bundles called packets. The packets contained address, error-control, and sequencing information. The address information allowed packets to be routed to their destinations.

TCP/IP

The protocol (i.e., set of rules) for communicating over the ARPANET became known as TCP—the Transmission Control Protocol. TCP ensured that messages were properly routed from sender to receiver and that they arrived intact.

URIs

URIs (Uniform Resource Identifiers) identify resources on the Internet .

URLs

URIs that start with http:// are called URLs (Uniform Resource Locators).

Client-side programming technologies

are used to build web pages and applications that are run on the client (in the browser on the user's device)

jQuery

jQuery (jQuery.org) is currently the most popular of hundreds of JavaScript libraries.

Server-side programming

the applications that respond to requests from client-side web browsers, such as searching the Internet, checking your bank account balance, ordering a book from Amazon, bidding on an eBay auction and ordering concert tickets.