What is PHP?
PHP stands for PHP Hypertext Preprocessor and is widely used for creating dynamic web pages. Dynamic web pages are able to generate content on demand, without a webmaster or author directly editing a web page. They are common among e-commerce websites, Internet forums, and websites that need to constantly update content in a timely fashion. PHP is often coupled with a database backend, sitting between the data and resulting web pages. PHP combines the flexibility of scripting with the simplicity, structure, and standardization of HTML.
Most of the time, PHP files on the Internet will manifest as a web page, where the page in the address bar may end in the extension .php or something similar. In these situations, you are viewing the resulting web page that was generated using the PHP file on the website, and can not download the raw PHP file. However, if you have downloaded a PHP file for scripting purposes, such as from a tutorial website or as part of a code package, then you will need to take special steps to open the PHP file for editing.
How do I open a PHP file?
A PHP file is like any other text file that you may be familiar with. Therefore, you can use readily-available programs such as Notepad on Windows, or TextEdit on a Mac, to open a PHP file. You can also use these programs to edit and save the PHP file. Additionally, there is a multitude of programs specifically designed for editing PHP files.
To open a PHP file in Notepad, first launch the Notepad application. In Notepad, select File, Open in the menu bar. Navigate to the folder where you saved the PHP file. You may notice that the file does not appear in the list. In order to see the PHP file, you will need to change the extension to All Files using the drop-down next to the File Name field. Now you should be able to select your PHP file, and click Open.
To open a PHP file in TextEdit, navigate to where the PHP file is located. Then, secondary click the file and select Open With, then TextEdit.
Special software exists to allow for easier viewing and editing of PHP files. One common feature of these programs is syntax highlighting. Syntax highlighting color-codes certain words, phrases, and characters that have special meaning in the programming or scripting language. While these programs may offer features that are not found in Notepad or TextEdit, they perform the same basic function of editing a text file. As such, you can open and save PHP files in the same way as described above.
Since PHP is designed to work alongside standard HTML, PHP files are often interwoven with HTML. In some cases, the majority of a PHP file may actually be HTML.
Why won’t PHP files open in my web browser?
Unlike HTML, PHP files are intended to be interpreted by special software installed on a web server. This software reads the PHP file and interprets all of the script commands, eventually performing some action and/or sending HTML back to your web browser to be displayed. While you can open PHP files and edit them in Notepad, TextEdit, or another file editing program, you cannot generate a web page by simply opening the PHP file in a web browser. You can read What is a PHP File for more information on the PHP scripting language.