Short notes on webpage programming languages
What is HTML?
HTML is a language for describing web pages.
• HTML stands for Hyper Text Markup Language
• HTML is a markup language
• A markup language is a set of markup tags
• The tags describe document content
• HTML documents contain HTML tags and plain text
• HTML documents are also called web pages
HTML Tags
HTML markup tags are usually called HTML tags
• HTML tags are keywords (tag names) surrounded by angle brackets like
<html>
• HTML tags normally come in pairs like <b> and </b>
• The first tag in a pair is the start tag, the second tag is the end tag
• The end tag is written like the start tag, with a forward slash before the tag name
• Start and end tags are also called opening tags and closing tags Syntax for a basic html page:
<!DOCTYPE html>
<html>
<body>
<h1>My name is …..</h1>
<p>My first paragraph</p>
</body>
</html>
Example Explained
• The DOCTYPE declaration defines the document type
• The text between <html> and </html> describes the web page
• 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
HTML Hyperlinks (Links)
• The HTML <a> tag defines a hyperlink.
• A hyperlink (or link) is a word, group of words, or image that you can click on to jump to another document.
• When you move the cursor over a link in a Web page, the arrow will turn into a little hand.
• The most important attribute of the <a> element is the ‘href’ attribute, which indicates the link's destination.
By default, links will appear as follows in all browsers:
• An unvisited link is underlined and blue
• A visited link is underlined and purple
• An active link is underlined and red
HTML Link Syntax
• The HTML code for a link is simple. It looks like this:
• <a href="url">Link text</a>
• The href attribute specifies the destination of a link.
Example:
<a href="http://www.w3schools.com/">Visit W3Schools</a>
HTML Images - The <img> Tag and the Src Attribute
• In HTML, images are defined with the <img> tag.
• The <img> tag is empty, which means that it contains attributes only, and has no closing tag.
• To display an image on a page, you need to use the src attribute. Src stands for "source".
• The value of the src attribute is the URL of the image you want to display.
• Syntax for defining an image:
• <img src="url" alt="some_text">
Example:
<img src="smiley.gif" alt="Smiley face
What is CSS?
• CSS stands for Cascading Style Sheets
• Styles define how to display HTML elements
• Styles were added to HTML 4.0 to solve a problem
• External Style Sheets can save a lot of work
• External Style Sheets are stored in CSS files
JavaScript is a Scripting Language
• A scripting language is a lightweight programming language.
• JavaScript is programming code that can be inserted into HTML pages.
What is XML
• XML stands for eXtensible Markup Language.
• XML is designed to transport and store data.
• XML is important to know, and very easy to learn
Classic ASP - Active Server Pages
• Active Server Pages (ASP), also known as Classic ASP, was introduced in 1998 as Microsoft's first server side scripting engine.
• ASP is a technology that enables scripts in web pages to be executed by an Internet server.
• ASP pages have the file extension .asp, and are normally written in VBScript.
• If you want to learn Classic ASP
ASP.NET
• ASP.NET is a new ASP generation. It is not compatible with Classic ASP, but ASP.NET may include Classic ASP.
• ASP.NET pages are compiled, which makes them faster than Classic ASP.
• ASP.NET has better language support, a large set of user controls, XML-‐
based components, and integrated user authentication.
• ASP.NET pages have the extension .aspx, and are normally written in VB (Visual Basic) or C# (C sharp).
• User controls in ASP.NET can be written in different languages, including C++ and Java.
When a browser requests an ASP.NET file, the ASP.NET engine reads the file, compiles and executes the scripts in the file, and returns the result to the browser as plain HTML.
What is PHP?
• PHP is an acronym for "PHP Hypertext Preprocessor"
• PHP is a widely-‐used, open source scripting language
• PHP scripts are executed on the server
• PHP costs nothing, it is free to download and use
What is a PHP File?
• PHP files can contain text, HTML, CSS, JavaScript, and PHP code
• PHP code are executed on the server, and the result is returned to the browser as plain HTML
• PHP files have extension ".php"
What Can PHP Do?
• PHP can generate dynamic page content
• PHP can create, open, read, write, and close files on the server
• PHP can collect form data
• PHP can send and receive cookies
• PHP can add, delete, modify data in your database
• PHP can restrict users to access some pages on your website
• PHP can encrypt data
With PHP you are not limited to output HTML. You can output images, PDF files, and even Flash movies. You can also output any text, such as XHTML and XML.
Why PHP?
• PHP runs on various platforms (Windows, Linux, Unix, Mac OS X, etc.)
• PHP is compatible with almost all servers used today (Apache, IIS, etc.)
• PHP supports a wide range of databases
• PHP is free. Download it from the official PHP resource: www.php.net
• PHP is easy to learn and runs efficiently on the server side
What is SQL?
• SQL stands for Structured Query Language
• SQL lets you access and manipulate databases
• SQL is an ANSI (American National Standards Institute) standard
What Can SQL do?
• SQL can execute queries against a database
• SQL can retrieve data from a database
• SQL can insert records in a database
• SQL can update records in a database
• SQL can delete records from a database
• SQL can create new databases
• SQL can create new tables in a database
• SQL can create stored procedures in a database
• SQL can create views in a database
• SQL can set permissions on tables, procedures, and views
SQL is a Standard - BUT....
However, to be compliant with the ANSI standard, they all support at least the major commands (such as SELECT, UPDATE, DELETE, INSERT, WHERE) in a similar manner.
Note: Most of the SQL database programs also have their own proprietary extensions in addition to the SQL standard!
Using SQL in Your Web Site
To build a web site that shows data from a database, you will need:
• An RDBMS database program (i.e. MS Access, SQL Server, MySQL)
• To use a server-‐side scripting language, like PHP or ASP
• To use SQL to get the data you want
• To use HTML / CSS
RDBMS
• RDBMS stands for Relational Database Management System.
• RDBMS is the basis for SQL, and for all modern database systems such as MS SQL Server, IBM DB2, Oracle, MySQL, and Microsoft Access.
• The data in RDBMS is stored in database objects called tables.
• A table is a collection of related data entries and it consists of columns and rows.
