These are the basic knowledge required to be able to get started with PHP progamming.
Table of contents
HTML stands for HyperText Markup Language (translated as HyperText Markup Language) used to create a web page. A website can contain many pages and each page is referred to as an HTML document.
Below is an example of one of the simplest examples of an HTML document.
<!DOCTYPE html>
<html>
<head>
<title>This is Title Tag</title>
</head>
<body>
<h1>This is H1 Tag</h1>
<p>This is P Tag</p>
</body>
</html>Tags in HTML - Tags in HTML
HTML is tag language and uses different tags to format the content. These tags are contained within two parentheses .
Except for a few tags, most tags have their corresponding closing tags. For example, the tag <html> has a close tag of </html>, and the <body> tag has a corresponding close tag of </body>...
Website has two main types:
- Static website - Is a website that does not communicate with the web server to send and receive data but only the data is pre-declared by HTML and the browser to read.
- Dynamic website - A website that will communicate with a server to send and receive data, the data will be sent out to the user using HTML text and the browser will display it. In order for a website to communicate with the web server, it will use some server-side programming languages such as PHP, ASP.NET, Ruby, .. to perform. For example, a website made of WordPress is a dynamic website.
Basic html tags need to know:
- HTML Headings
- HTML Paragraphs
- HTML Attributes
- HTML Colors
- HTML Links
- HTML Images
- HTML Tables
- HTML Lists
- HTML JavaScript
- HTML Responsive Web Design
- HTML Forms
To learn more about the other tags and their meanings, you can find out at the following link:
https://www.w3schools.com/html
CSS is a language to create style for the website - Cascading Style Sheet language. It is used to style and style elements written in markup language, such as HTML. It can control the formatting of multiple web pages at the same time to save the effort of web writers. It distinguishes the appearance of the web page from the main content of the page by controlling the layout, color, and font.
Here is an example of one of the simplest Css templates.
body {
background-color: black;
color: #fff;
}The above Css will define all the html elements in the body tag, the background image will be black and the text is white.
Embed CSS in HTML
Inline: CSS code written in the style attribute of the HTML element
<p style="color:white; background-color:red;"></p>Internal: the CSS code in the HTML document itself, inside the tag block <style>
<html>
<head>
<link rel="stylesheet" href="demo.css">
</head>
</html>External: CSS code in a separate file then loaded into HTML with the element <link>
<html>
<head>
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css" />
</head>
<body>
<p class="display-1 text-success">Hello CSS</p>
</body>
</html>Css specific syntax
-
Selector The HTML element name at the beginning of the rule set. It selects the styled element (s) (p element in this case). To style another element, simply change the selector. Declaration A single rule like: color: red; specifies which element properties you want to style.
-
Properties Ways you can style an HTML element. (In this case, color is an attribute of the
<p>element.) In CSS, you choose which property you want to affect in your rule. -
Attribute value To the right of the property after the colon (:), we have the property value, which chooses one out of as many possible occurrences for a particular property (color has a lot of values beyond red).
Basic CSS need to know:
- CSS Colors
- CSS Backgrounds
- CSS Borders
- CSS Margins
- CSS Padding
- CSS Height and Width
- CSS Dropdowns
- CSS Forms
- CSS Transitions
- CSS Animation
- CSS Buttons
- CSS Pagination
- CSS Responsive
To learn more about other properties of CSS, learn more at the following link:
To write CSS in a more professional, fast and coherent way, we will write css using SASS or SCSS.
The first concept to know is CSS Preprocessors.
CSS Preprocessors is a scripting language that extends CSS and is compiled into CSS syntax to help you write CSS faster and have a clearer structure. CSS Preprocessor can save you time writing CSS, easy maintenance and development of CSS.
Basic SASS / SCSS need to know:
- Sass Variables
- Sass @import
- Sass @mixin
- Sass Functions
To learn more about other properties of CSS, learn more at the following link:
https://www.w3schools.com/sass/
PHP (Personal Home Page) is an open source scripting language commonly used to create web applications running on servers. PHP code can be embedded in an HTML page using the PHP Tag pair.
<!DOCTYPE html>
<html>
<head>
<title>Embeds the PHP code and the HTML page</title>
</head>
<body>
<?php
echo "Hello PHP!";
?>
</body>
</html>- The extension to be used is .php
- PHP code is placed in the snippet
<? Php?> - Place a semicolon at the end of each line of code
<?php
echo ‘Hello World’;
# This is comment
?>How to comment code
Comment lines are comments to aid in reading and understanding code.
Writing comments code isn't always mandatory, but writing them can help with future review.
There are 3 ways to write comments in PHP code as follows:
- Type "//" at the beginning of the line
- Type "#" at the beginning of the line
- Or wrap the comment between the two signs "/" and "/"
Basic Syntax
Declare variable
When writing software, there are reusable information strings that are saved as variables.
Variables can be used to store almost any type of data, from long text strings to numbers, true-false (Boolean) ...
However, PHP has some predefined variables that cannot be overridden, such as $ GLOBALS, or $ _GET.
For example we have the following code:
<?php
$name = ‘NCC’;
echo $name;
?>Then, the text "NCC" will be displayed on the interface, since it is saved as a string in the variable "$ name", the variable "$ name" can then be changed according to the logic of the application.
There are several rules for defining variables in PHP as follows:
Begin with the dollar character ($)
But characters allowed for variable names include a-z, A-Z, 0-9, and _
Variable names starting with digits 0-9 cannot be named
Japanese can also be used as variable names, but it shouldn't be
Naming variables are not too strict but should be set so that it is clear, easy to understand, and true of the variable nature.
PHP Data Types PHP supports the following data types:
- String
- Integer
- Float (floating point numbers - also called double)
- Boolean
- Array
- Object
- NULL
- Resource
Operators
Operators in PHP are symbols that can be used in calculations.
There are arithmetic operators such as addition, subtraction, multiplication, comparison, or operators used for inference ...
For example we have the following code:
<?php
$sum = 2 + 3;
echo “2 + 3 = $sum”;
?>PHP if...else...elseif Statements The "if" snippet is often used to check if the next part has a true (TRUE) value, and will execute the internal code if the above condition is met.
<?php
$condition = 3;
if ($condition === 3) {
echo “Conditions”;
} else {
echo “Unsatisfactory”;
}
?>Thus, the text "Conditions" will be displayed for the value of the variable "$ condition" equal to 3.
The "while" code is used to run the code repeatedly, until the while condition is no longer satisfied.
<?php
$increment = 1;
while ($increment <= 5) {
echo “Run 5 times”;
$increment++;
}
?>The text "Run 5 times" will display exactly 5 times on the screen, until the variable "$ increment" is incremented by 1 after 5 loops and the final value after 5 increments are greater than 5.
Function declaration
Functions in PHP are groups of code that are grouped and can be executed when the function is called.
For example we have the following sum function:
<?php
function sum ($a, $b) {
return $a + $b;
}
?>When calling the function "sum" as follows, we get the sum of 2 numbers is 5 and it is displayed on the interface:
<?php
echo sum(2, 3);
?>Others Basic PHP need to know
- PHP Forms: PHP Form Handling, PHP Form Validation, PHP Form Required ...
- PHP Switch
- PHP Loops
- PHP Constants
- PHP Numbers
To learn more about PHP, you can refer to the following link: https://www.w3schools.com/php
Magic methods are special methods which override PHP's default's action when certain actions are performed on an object.
- https://www.php.net/manual/en/language.oop5.decon.php#object.construct
- https://www.php.net/manual/en/language.oop5.magic.php#object.tostring
- https://www.php.net/manual/en/language.oop5.magic.php#object.serialize
Traits are a mechanism for code reuse in single inheritance languages such as PHP. A Trait is intended to reduce some limitations of single inheritance by enabling a developer to reuse sets of methods freely in several independent classes living in different class hierarchies.
PHP runs on Zend Engine platform. Zend Engine takes care of interpreting PHP code into machine code and executing it.
Zend Engine itself provides a number of libraries available so that PHP can run directly without an external library, but most of those libraries are Text processing libraries. The other PHP libraries are written in the form of extensions, these libraries mainly work with PHP through the Zend Engine. Some of PHP's I/O processing is through external libraries, not core support: for example, DB connection, working with HTTP, image processing ...
Here are the popular PHP extensions that often required in your future work:
- bcMath
- cURL
- mcrypt
- php-mysql
You can install a PHP extension using one of the following methods:
-
Using a package manager: If your web server is running on a Linux or UNIX-based system, you can use a package manager such as apt-get or yum to install the extension. For example, to install the MySQL extension on Ubuntu, you can use the command: sudo apt-get install php-mysql
-
Using the PECL command: PECL is a repository for PHP extensions. You can use the PECL command to install an extension. For example, to install the MongoDB extension, you can use the command: pecl install mongodb
-
Compiling from source: You can also install an extension by downloading the source code and compiling it yourself. This is typically more advanced and is not recommended for beginners.
Once you have installed the extension, you will need to check the php.ini file, find the line ;extension=module.so and remove the ; before the extension you want to enable. After that restart your web server for the changes to take effect.
It's worth noting that some extensions may have additional dependencies that need to be installed as well.
Here are some basic components of a web service
When you download a web browser, you get HTML, CSS, and JavaScript, but you do not get PHP. PHP scripts—which you’ll soon be writing—have to be interpreted by the PHP interpreter program, called php. And, you can’t just add a PHP interpreter to your browser. It doesn’t know what to do with scripts and isn’t built to interpret PHP.
Instead, you need PHP on a web server. It’s the web server — not the web browser — that can interact with a PHP interpreter. Your browser can handle HTML on its own, but it has to make a request to a web server to deal with PHP scripts. That server can take your PHP scripts and run them, and then take the response and send it back to your browser. Your browser can then understand and handle the response.
Here’s the basic process:
- A web browser makes a request for some page. That page might be a URL on a remote web server, or a local file on your computer.
- The web server returns HTML (and CSS and JavaScript) or, in the case of PHP, passes the PHP request on to the PHP interpreter.
- The PHP interpreter interprets, or runs, the PHP. The result of that should be something that a browser can understand, like HTML, JSON string. It passes this result, or response, back to the web server and later the web browser.
- Install markdown extension and run preview this repository using markdown extension
- Host a basic html page on your local machine
- Host a basic php file (return a string 'Hello world') on your local machine
- Check the above popular PHP extensions already installed in your local machine