How a PHP request starts and ends - Quick Revision & Summary

Recall & Review

beginner

What happens first when a PHP request starts?

The web server receives the request and passes it to the PHP interpreter to start processing the PHP script.

beginner

What role does the PHP interpreter play during a request?

It reads the PHP code, executes it line by line, and generates output like HTML to send back to the browser.

beginner

How does a PHP request end?

After executing the script, PHP sends the output to the web server, which then sends it to the user's browser, and the PHP process finishes.

intermediate

What happens if PHP encounters an error during the request?

PHP stops executing the script and shows an error message or logs it, depending on the configuration.

beginner

Why is the PHP request lifecycle important to understand?

Knowing it helps you write efficient code and debug issues by understanding when and how your code runs.

What is the first step in a PHP request?

A The web server passes the request to PHP

B PHP sends output to the browser

C The browser executes PHP code

D PHP finishes the request

The web server receives the request and hands it over to PHP to start processing.

What does PHP do during a request?

A Executes the PHP script and generates output

B Stores the request in a database

C Sends the request to the browser without changes

D Waits for user input

PHP reads and runs the script, then creates output like HTML for the browser.

When does a PHP request end?

A When the browser closes

B After PHP sends output to the web server

C Before PHP starts executing code

D When the user logs out

The request ends after PHP finishes running the script and sends the output back.

What happens if PHP encounters an error during execution?

A It sends a success message

B It ignores the error and continues

C It restarts the request automatically

D It stops and shows or logs an error

PHP stops running the script and reports the error based on settings.

Why should you understand the PHP request lifecycle?

A To design websites without PHP

B To avoid using PHP altogether

C To write better code and debug effectively

D To speed up the browser

Understanding the lifecycle helps you know when your code runs and how to fix problems.

Describe the main steps that happen from when a PHP request starts until it ends.

Think about how the request moves from the browser to PHP and back.

Explain what happens if there is an error during a PHP request.

Consider how PHP handles problems while running your code.

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