Let's create your first PHP application together-PHP Problem-php.cn

Let's create your first PHP application together

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Release： 2022-06-21 08:57:12

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PHP is an incredibly powerful programming language that powers about 80% of the web! But it's also an easier language to learn because you can see your changes in real time without having to compile or wait for code to repackage your app or website.

Define PHP script

First, create a file named "myfirstpage.php". Actually, you can call it whatever you want, but the important part here is the extension: .php. This tells the server to treat this page as a PHP script.

Now let's go ahead and create a basic HTML page:

<html>
<head>
<title>Hello</title>
</head>
<body>
Hello
</body>
</html>

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Go ahead and save your page and upload it to any host that supports PHP. Now visit your page and you should see a page that prints "Hello".

Now let’s add some PHP code to the script. In order to notify the server to render PHP code, we first open it with the tag. This is important, as if we are creating an XML file and forget to escape the opening XML tag which also has a question mark, we will encounter a fatal error.

Now let's write some PHP code that tells the server to display specific output. To echo or print the content on the page, we can use the echo statement in PHP code by placing the text to be echoed in single quotes and ending the command with a semicolon. echo "there!":

<html>
<head>
<title>Hello</title>
</head>
<body>
Hello <?php echo &#39;there!&#39;; ?>
</body>
</html>

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Now upload your script and test it on your virtual host. You should now see "there!" on your screen. Now this is less exciting because we can do the same thing in HTML without PHP, so let's create dynamic content based on a URL string.

Using $_GET

PHP allows you to interact with visitors and process incoming data. This means you can use a URL (query string) or a form to retrieve user input. There are other ways to access data, but we won't cover those in this introduction.

In your browser, add the following to the end of your URL: ?name=yourname

The complete URL should now look like myfirstpage.php?name=yourname

When you visit this page, you'll notice that nothing happens - so let's change that! To access the value in the name query string, we can use $_GET['name'] like this:

<html>
<head>
<title>Hello</title>
</head>
<body>
Hello <?php echo $_GET[&#39;name&#39;]; ?>
</body>
</html>

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You will notice that unlike the text "there!" GET is not in quotes - this is because this is a variable, and by not putting it in quotes, we are telling PHP to render it as a variable rather than text. If we leave the single quotes out, the output is "Hello$_GET['name']"

At this point, you have created your first PHP script and have taken advantage of the Lots of basics. While there's more to learn, you're on the right track and have a good start in defining variables, working with user input, and leveraging PHP's built-in functions.

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