Html php web application

Your first PHP-enabled page

Create a file named hello.php and put it in your web server’s root directory ( DOCUMENT_ROOT ) with the following content:

Example #1 Our first PHP script: hello.php

Use your browser to access the file with your web server’s URL, ending with the /hello.php file reference. When developing locally this URL will be something like http://localhost/hello.php or http://127.0.0.1/hello.php but this depends on the web server’s configuration. If everything is configured correctly, this file will be parsed by PHP and the following output will be sent to your browser:

This program is extremely simple and you really did not need to use PHP to create a page like this. All it does is display: Hello World using the PHP echo statement. Note that the file does not need to be executable or special in any way. The server finds out that this file needs to be interpreted by PHP because you used the «.php» extension, which the server is configured to pass on to PHP. Think of this as a normal HTML file which happens to have a set of special tags available to you that do a lot of interesting things.

If you tried this example and it did not output anything, it prompted for download, or you see the whole file as text, chances are that the server you are on does not have PHP enabled, or is not configured properly. Ask your administrator to enable it for you using the Installation chapter of the manual. If you are developing locally, also read the installation chapter to make sure everything is configured properly. Make sure that you access the file via http with the server providing you the output. If you just call up the file from your file system, then it will not be parsed by PHP. If the problems persist anyway, do not hesitate to use one of the many » PHP support options.

The point of the example is to show the special PHP tag format. In this example we used . You may jump in and out of PHP mode in an HTML file like this anywhere you want. For more details, read the manual section on the basic PHP syntax.

Note: A Note on Line Feeds

Line feeds have little meaning in HTML, however it is still a good idea to make your HTML look nice and clean by putting line feeds in. A linefeed that follows immediately after a closing ?> will be removed by PHP. This can be extremely useful when you are putting in many blocks of PHP or include files containing PHP that aren’t supposed to output anything. At the same time it can be a bit confusing. You can put a space after the closing ?> to force a space and a line feed to be output, or you can put an explicit line feed in the last echo/print from within your PHP block.

Note: A Note on Text Editors

There are many text editors and Integrated Development Environments (IDEs) that you can use to create, edit and manage PHP files. A partial list of these tools is maintained at » PHP Editors List. If you wish to recommend an editor, please visit the above page and ask the page maintainer to add the editor to the list. Having an editor with syntax highlighting can be helpful.

Note: A Note on Word Processors

Word processors such as StarOffice Writer, Microsoft Word and Abiword are not optimal for editing PHP files. If you wish to use one for this test script, you must ensure that you save the file as plain text or PHP will not be able to read and execute the script.

Now that you have successfully created a working PHP script, it is time to create the most famous PHP script! Make a call to the phpinfo() function and you will see a lot of useful information about your system and setup such as available predefined variables, loaded PHP modules, and configuration settings. Take some time and review this important information.

Example #2 Get system information from PHP

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Создание простейшего веб приложения на PHP + MySQL

Начиная с текущего урока мы начнем создавать простейшее веб приложение с использованием php и mysql. Оно будет основано на базе данных sport, которую мы создали на прошлых уроках при знакомстве с Mysql. В этом уроке мы определим структуру нашего приложения, напишем скрипт соединения с базой данных, а также построим скелет нашего приложения.

Структура:
Конфигурация (db.php — подключение к БД)
1. Главная страница — index.php (форма авторизации)
2. Команды (teams.php — список команд с возможностью редактировать информацию о команде)
3. Игроки (players.php — список игроков с возможностью редактировать информацию об игроке)
4. Страны (countries.php — список команд по странам)

В своих проектах я использую универсальный драйвер PDO для работы с базой данных. Есть и другие варианты работы с базами данных, например mysql и mysqli. Сразу отмечу, что расширение mysql с версии php 5.5 считается устаревшим, а с версии 7 удалено.
Почему я использую PDO? Главным его преимуществом является универсальность: PDO может свободно работать с разными производителями СУБД, что делает переход из одной СУБД в другую с точки зрения php мене затратным. Дальнейшие детали и особенности работы с PDO мы рассмотрим в следующих уроках, в процессе написания нашего приложения.

Также в уроке вы узнаете о конструкции try…catch. Когда используется данная конструкция? В процессе создания программ возникают ошибки (ошибки логики, опечатки и т.п), но могут возникать ошибки, которые вы изначально можете предусмотреть. Например, вы прекрасно понимаете, что соединение с БД может закончиться ошибкой, и эту ошибку необходимо предусмотреть.

Пример try. catch

После успешного соединения с базой данных мы напишем «скелет» внешнего вида главной страницы нашего приложения, используя bootstrap и jquery.

В заключении отмечу, что в следующую субботу мы с моим коллегой планируем провести стрим на youtube канале на тему «MySQL. Полезные приемы и особенности работы с MySQL». О точном времени будет сообщено позже.

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Write your first PHP application

In this tutorial we introduce you to writing and running a simple PHP application. We will learn some PHP syntax, how we can integrate HTML in a PHP file and how to run the application in a web browser.

Before we begin

Before you begin, you must have a PHP parser installed on your system.

If you don’t have an environment set up yet, please follow one of the links below before continuing.

Your first PHP application

First things first, if you haven’t started the web server yet, open the XAMPP Control and start the Apache web server module. Without it, we won’t be able to run our application.

Next, we need to create a file to hold the PHP code.

1. Open your Atom IDE. In the Project Pane on the left, right-click on the PHPProjects folder and select New File.
2. Name the file HelloWorld.php and press Enter or Return on your keyboard.

Write the code below into your HelloWorld.php file and save it by going to File > Save.

 In your web browser navigate to the url: localhost/PHPProjects/HelloWorld.php

You should see the words “Hello World” on the page.

If you gave your project folder or php file a different name, please make sure that reflects in the url, otherwise the PHP script won’t run.

Breakdown of your first PHP application

In this breakdown, we will go through the code line by line so you can have a basic understanding of the syntax of a PHP application.

Open and close tags

The open and close tags in PHP indicate a dedicated space between them for PHP code. PHP cannot parse code outside of these tags.

The interpreter will scan the document, looking for these tags. When it finds them, it will attempt to execute the code within.

Other types of code, such as HTML, is allowed within the document. Because of this, we explicitly tell the interpreter where the PHP code is written.

If there were no open and close tags, PHP scripts that contain other types of code could become confusing quickly and the interpreter might misinterpret conflicting code and break the application.

Comments

PHP allows us to document our code, and one of the ways we do that is with comments. Comments are completely ignored by the interpreter at runtime.

Single line comments are prefixed with two forward slashes // . Anything on that same line, after the forward slashes, will be ignored by the interpreter.

 If you’re working in an IDE, it will usually recolor comments into a grey color to indicate that the code is a comment.

The echo command statement

The echo statement in PHP is a command statement that will display whatever comes after it on the page.

 In this particular case we print the words “Hello World”, known as a string, on the page. The contents of a string are always enclosed within quotes.

 At the end of the command we write a semicolon operator ; . A semicolon is a statement terminator and indicates to the interpreter that this command is ended at this point.

As we’ve mentioned previously, PHP can be written alongside other languages, like HTML, in the same document.

When writing PHP in a document with HTML code, we must remember that the document must be a PHP type document with the .php extension.

If we write PHP code in a document with a .html extension, it will not be executed.

Quick HTML Intro

HTML is a markup language, it uses opening and closing tags to specify elements in a hierarchical fashion. Inside these elements we can specify text, links and images which will be shown on a webpage.

The following is an example of what an HTML tag pair looks like.

An open tag is written by using a keyword in between a less than and a greater than > symbol.

A close tag is written the same as an open tag but has a forward slash in front of the keyword.

 The most basic html document consists of , and tags. The head and body tags are nested inside the html tags.

Clear the PHP code we wrote earlier from the HelloWorld.php document and copy & paste the HTML below into the file.

Now that we have some HTML to work with we’ll write our PHP code inside of it. We want to write the same echo statement, but this time inside the tag in the body of the HTML.

In between the open and close tags, we simply write the same PHP code that we did in the very first example, only this time we write it all on one line.

When we refresh the webpage in the browser we can see that the text “Hello World” is now a heading, bigger and bold.

We have successfully written both a PHP only application and a PHP webpage.

Summary: Points to remember

• PHP code will only be executed in a document with the .php extension.
• PHP code will only be executed if it is wrapped in open and close PHP tags:
• We can combine PHP with other languages like HTML by writing the HTML inside our .php document.

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