How a PHP request starts and ends

Introduction

PHP runs code when a web page is requested and stops when the page is done. This helps create dynamic websites.

When a user visits a webpage that uses PHP to show content.

When a form is submitted and PHP processes the data.

When a server needs to run PHP code to get information from a database.

When you want to create a page that changes based on user input.

When you want to send an email or save data after a user action.

Syntax

PHP

<?php
// PHP code here
?>

PHP code starts with <?php and ends with ?>.

The server runs the PHP code between these tags when the page is requested.

Examples

This example shows a simple PHP script that prints text to the page.

PHP

<?php
echo "Hello, world!";
?>

This example shows PHP code running when the page loads and then stopping after finishing.

PHP

<?php
// Start of PHP request
$name = "Alice";
echo "Welcome, $name!";
// End of PHP request
?>

Sample Program

This program shows how PHP code runs from start to end during a page request. It prints a message and then stops.

PHP

<?php
// This simulates a PHP request

// Start: PHP code runs when page is requested
$message = "Hello from PHP!";
echo $message;

// End: PHP stops after sending output
?>

Important Notes

PHP runs only when a page is requested and stops after sending the response.

Each request is separate; PHP does not keep running after the page loads.

Use PHP tags to tell the server where your PHP code starts and ends.

Summary

PHP code runs between <?php and ?> tags.

A PHP request starts when a page is requested and ends after the server sends the response.

Each request is independent and runs the PHP code fresh every time.

Practice

1. What marks the beginning of PHP code in a file?

easy

A. The <php> tag

B. The <script> tag

C. The <?php tag

D. The <?> tag

Solution

1. Step 1: Identify PHP opening tag

   PHP code always starts with the <?php tag to tell the server to process PHP.

2. Step 2: Compare with other tags

   Other tags like <script> are for JavaScript, and <php> is invalid.

3. Final Answer:

   The <?php tag -> Option C

4. Quick Check:

   PHP starts with <?php [OK]

Hint: PHP code always starts with <?php tag [OK]

Common Mistakes:

• Confusing PHP tags with HTML or JavaScript tags
• Using short tags like which may be disabled
• Thinking PHP starts with ? or other symbols

2. Which of the following correctly ends a PHP block?

easy

A. ?>

B. </php>

C. <?php

D. <?>

Solution

1. Step 1: Identify PHP closing tag

   The PHP block ends with ?> to signal the end of PHP code.

2. Step 2: Validate other options

   </php> is invalid HTML, <?php starts PHP, and <?> is not a valid closing tag.

3. Final Answer:

   ?> -> Option A

4. Quick Check:

   PHP ends with ?> [OK]

Hint: PHP ends with ?> tag to close code block [OK]

Common Mistakes:

• Using HTML closing tags like
• Confusing PHP start and end tags
• Omitting the closing tag when mixing PHP and HTML

3. What will be the output of this PHP code?

<?php
echo 'Hello';
?>

medium

A. Hello

B. <?php echo 'Hello'; ?>

C. Syntax Error

D. No output

Solution

1. Step 1: Understand PHP code execution

   The PHP code inside <?php ?> runs on the server and outputs the string 'Hello'.

2. Step 2: Check output behavior

   The echo statement prints 'Hello' to the page, so the output is exactly that.

3. Final Answer:

   Hello -> Option A

4. Quick Check:

   echo 'Hello' outputs Hello [OK]

Hint: echo prints text inside PHP tags to the page [OK]

Common Mistakes:

• Expecting PHP code to show as text in browser
• Confusing PHP tags with HTML tags
• Thinking PHP code causes syntax error without semicolon

4. Identify the error in this PHP snippet:

<?php
echo 'Hi'
?>

medium

A. Incorrect PHP start tag

B. Using single quotes instead of double quotes

C. Missing closing PHP tag

D. Missing semicolon after echo statement

Solution

1. Step 1: Check PHP syntax rules

   Each PHP statement must end with a semicolon; here, echo 'Hi' lacks it.

2. Step 2: Validate other parts

   The start tag <?php and closing tag ?> are correct; single quotes are valid in PHP.

3. Final Answer:

   Missing semicolon after echo statement -> Option D

4. Quick Check:

   Statements need semicolon [OK]

Hint: Every PHP statement ends with a semicolon [OK]

Common Mistakes:

• Forgetting semicolon at end of statements
• Thinking PHP tags are case-sensitive
• Assuming quotes type causes syntax error

5. Which statement best describes how a PHP request lifecycle works?

hard

A. PHP code runs once when the server starts and stays in memory

B. Each request runs PHP code fresh, then ends after sending response

C. PHP code runs only if the closing tag is omitted

D. PHP code runs continuously until manually stopped

Solution

1. Step 1: Understand PHP request lifecycle

   PHP runs code fresh on each page request, processes it, then ends after sending the response.

2. Step 2: Evaluate other options

   PHP does not run continuously or stay in memory; closing tag presence does not control execution.

3. Final Answer:

   Each request runs PHP code fresh, then ends after sending response -> Option B

4. Quick Check:

   PHP runs per request, then ends [OK]

Hint: PHP runs fresh on each request, then stops [OK]

Common Mistakes:

• Thinking PHP code runs persistently like a service
• Believing PHP runs only if closing tag is missing
• Assuming PHP code stays loaded between requests