Web Engineering

Web engineering actively promotes systematic, disciplined and quantifiable approaches towards successful development of high-quality, universally usable web-based systems and applications.

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HyperText Markup Language:

HyperText Markup Language (HTML) is the main markup language for creating web pages and other information that can be displayed in a web browser.

HTML is written in the form of HTML elements consisting of tags enclosed in angle brackets (like <html>), within the web page content. HTML tags most commonly come in pairs like <h1> and </h1>, although some tags, known as empty elements, are unpaired, for example <img>. The first tag in a pair is the start tag, the second tag is the end tag (they are also called opening tags and closing tags). In between these tags web designers can add text, tags, comments and other types of text-based content.

The purpose of a web browser is to read HTML documents and compose them into visible or audible web pages. The browser does not display the HTML tags, but uses the tags to interpret the content of the page.

HTML elements form the building blocks of all websites. HTML allows images and objects to be embedded and can be used to create interactive forms. It provides a means to create structured documents by denoting structural semantics for text such as headings, paragraphs, lists, links, quotes and other items. It can embed scripts written in languages such as JavaScript which affect the behavior of HTML web pages.

What About HTML Deficiencies?
HTML is missing important features

There is no ability to control program execution in HTML. Other languages have looping or logic tests. These are not present in HTML. At it’s core, all HTML can do is tell a browser how to display text. Programming languages tend to be more precise as well. If a program error is encountered during evaluation of a “C” program, all progress is stopped and the programmer receives an error message. The program can’t be completed until it is correctly written. This is not a rigid requirement of HTML. Browsers have been modified to accept HTML code that is not absolutely correct. They process what they can and continue to display the page if at all possible.

This seems to indicate that HTML is just a document similar to what a word processor displays. While HTML doesn’t have program logic tests, functions or loops, these are supported by additions such as PHP or Javascript modules. The real programming is accomplished using the extensive features of those languages. HTML is merely used to hold the pieces in the correct order. In fact, PHP programs can be written to generate custom HTML. Maybe HTML is definitely not a programming language.

 

HTML Code Example:

<!DOCTYPE html>
<html>
<body>
<h1>My First Heading</h1>
<p>My first paragraph.</p>
</body>
</html>
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Example Explained

  • The DOCTYPE declaration defines the document type
  • The text between <html> and </html> describes the web page. Encloses the entire HTML document.These tags let the browser know to start reading and displaying the information presented within.
  • The text between <body> and </body> is the visible page content
  • The text between <h1> and </h1> is displayed as a heading
  • The text between <p> and </p> is displayed as a paragraph

XHTML (Extensible HyperText Markup Language) is a family of XML markup languages that mirror or extend versions of the widely used Hypertext Markup Language (HTML), the language in which web pages are written.

JavaScript (JS) is an interpreted computer programming language. It was originally implemented as part of web browsers so that client-side scripts may interact with the user, control the browser, communicate asynchronously and alter the document content that is displayed.

Server-side scripting is a technique used in website design which involves embedding scripts in an HTML source code which results in a user’s (client’s) request to the server website being handled by a script running server-side before the server responds to the client’s request. The scripts can be written in any of a number of server-side scripting languages available .

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What can Server Scripts Do?

  • Dynamically edit, change or add any content to a Web page
  • Respond to user queries or data submitted from HTML forms
  • Access any data or databases and return the result to a browser
  • Customize a Web page to make it more useful for individual users
  • Provide security since your server code cannot be viewed from a browser

Important: Because the scripts are executed on the server, the browser that displays the file does not need to support scripting at all!

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