Mangal's Blog

Thursday, February 5, 2015

PHP Introduction

PHP started out as a small open source project that evolved as more and more people found out how useful it was. Rasmus Lerdorf unleashed the first version of PHP way back in 1994.

PHP is a recursive acronym for "PHP: Hypertext Preprocessor".
PHP is a server side scripting language that is embedded in HTML. It is used to manage dynamic content, databases, session tracking, even build entire e-commerce sites.
It is integrated with a number of popular databases, including MySQL, PostgreSQL, Oracle, Sybase, Informix, and Microsoft SQL Server.
PHP is pleasingly zippy in its execution, especially when compiled as an Apache module on the Unix side. The MySQL server, once started, executes even very complex queries with huge result sets in record-setting time.
PHP supports a large number of major protocols such as POP3, IMAP, and LDAP. PHP4 added support for Java and distributed object architectures (COM and CORBA), making n-tier development a possibility for the first time.
PHP is forgiving: PHP language tries to be as forgiving as possible.
PHP Syntax is C-Like.

Common uses of PHP:

PHP performs system functions, i.e. from files on a system it can create, open, read, write, and close them.
PHP can handle forms, i.e. gather data from files, save data to a file, thru email you can send data, return data to the user.
You add, delete, modify elements within your database thru PHP.
Access cookies variables and set cookies.
Using PHP, you can restrict users to access some pages of your website.
It can encrypt data.

Characteristics of PHP

Five important characteristics make PHP's practical nature possible:

Simplicity
Efficiency
Security
Flexibility
Familiarity

"Hello World" Script in PHP:

To get a feel for PHP, first start with simple PHP scripts. Since "Hello, World!" is an essential example, first we will create a friendly little "Hello, World!" script.

As mentioned earlier, PHP is embedded in HTML. That means that in amongst your normal HTML (or XHTML if you're cutting-edge) you'll have PHP statements like this:

<html>
<head>
<title>Hello World</title>
<body>
    <?php echo "Hello, World!";?>
</body>
</html>

Thursday, January 15, 2015

HTML Formatting Elements

In the previous chapter, you learned about HTML styling, using the HTML style attribute.

HTML also defines special elements, for defining text with a special meaning.

HTML uses elements like and for formatting output, like bold or italic text.

Formatting elements were designed to display special types of text:

Bold text
Important text
Italic text
Emphasized text
Marked text
Small text
Deleted text
Inserted text
Subscripts
Superscripts

Comment is a piece of code which is ignored by any web browser. It is a good practice to add comments into your HTML code, especially in complex documents, to indicate sections of a document, and any other notes to anyone looking at the code. Comments help you and others understand your code and increases code readability.

HTML comments are placed in between  tags. So any content placed with-in  tags will be treated as comment and will be completely ignored by the browser.

Example

<!DOCTYPE html>
<html>
<head>  <!-- Document Header Starts -->
<title>This is document title</title>
</head> <!-- Document Header Ends -->
<body>
<p>Document content goes here.....</p>
</body>
</html>

Monday, January 12, 2015

Horizontal Lines

Horizontal lines are used to visually break up sections of a document. The <hr> tag creates a line from the current position in the document to the right margin and breaks the line accordingly.

For example you may want to give a line between two paragraphs as in the given example below:

<!DOCTYPE html>
<html>
<head>
<title>Horizontal Line Example</title>
</head>
<body>
<p>This is paragraph one and should be on top</p>
<hr />
<p>This is paragraph two and should be at bottom</p>
</body>
</html>

Centering Content

You can use <center> tag to put any content in the center of the page or any table cell.

<!DOCTYPE html>
<html>
<head>
<title>Centring Content Example</title>
</head>
<body>
<p>This text is not in the center.</p>
<center>
<p>This text is in the center.</p>
</center>
</body>
</html>

Line Break Tag

Whenever you use the   element, anything following it starts from the next line. This tag is an example of an empty element, where you do not need opening and closing tags, as there is nothing to go in between them.

The tag has a space between the characters br and the forward slash. If you omit this space, older browsers will have trouble rendering the line break, while if you miss the forward slash character and just use it is not valid in XHTML

<!DOCTYPE html>
<html>
<head>
<title>Line Break  Example</title>
</head>
<body>
<p>Hello<br />
You delivered your assignment ontime.<br />
Thanks<br />
Mahnaz</p>
</body>
</html>

Paragraph Tag

The  tag offers a way to structure your text into different paragraphs. Each paragraph of text should go in between an opening and a closing tag as shown below in the example:

<!DOCTYPE html>
<html>
<head>
<title>Paragraph Example</title>
</head>
<body>
<p>Here is a first paragraph of text.</p>
<p>Here is a second paragraph of text.</p>
<p>Here is a third paragraph of text.</p>
</body>
</html>