How PHP executes on the server - Quick Revision & Summary

Recall & Review

beginner

What happens first when a PHP file is requested by a browser?

The web server receives the request and passes the PHP file to the PHP engine for processing.

beginner

What role does the PHP engine play in executing PHP code?

The PHP engine reads the PHP code, executes it on the server, and generates HTML or other output to send back to the browser.

beginner

Does the browser see the PHP code when a PHP page is loaded?

No, the browser only receives the output generated by PHP, usually HTML, not the PHP code itself.

beginner

Where does PHP code run: on the client or the server?

PHP code runs on the server before the page is sent to the client (browser).

beginner

What is the final output sent from the server to the browser after PHP execution?

The final output is usually HTML, but it can also be JSON, XML, or other data formats depending on the PHP script.

When a PHP file is requested, what does the server do first?

A Pass the file to the PHP engine for processing

B Send the PHP code directly to the browser

C Convert PHP code to JavaScript

D Ignore the request

The server sends the PHP file to the PHP engine to execute the code before sending output to the browser.

Where does PHP code run?

A On the server

B On the browser

C On the database

D On the network

PHP code runs on the server, not on the browser or client side.

What does the browser receive after PHP code execution?

A Server configuration files

B Raw PHP code

C HTML or other output generated by PHP

D PHP engine files

The browser receives the output generated by PHP, usually HTML, not the PHP code itself.

Can PHP code run directly in the browser?

A Only if JavaScript is enabled

B Yes, PHP runs in all browsers

C Only in some browsers

D No, PHP runs only on the server

PHP is a server-side language and cannot run directly in the browser.

What types of output can PHP generate?

A Only HTML

B HTML, JSON, XML, or other data formats

C Only images

D Only plain text

PHP can generate various output types like HTML, JSON, XML, depending on the script.

Explain the process of how PHP code is executed on the server when a user requests a PHP page.

Think about what happens from the moment you type a PHP page URL until you see the page.

Why does the browser never see the PHP code itself?

Consider where PHP code runs and what the browser receives.

Practice

1. What happens when a PHP file is requested by a browser?

easy

A. The PHP code is downloaded as a file to the browser

B. The browser runs the PHP code directly

C. The server runs the PHP code and sends the output to the browser

D. The server sends the PHP code as plain text to the browser

Solution

1. Step 1: Understand PHP execution location

   PHP code runs on the server, not in the browser.

2. Step 2: Identify what the browser receives

   The server sends only the output (usually HTML) to the browser, not the PHP code itself.

3. Final Answer:

   The server runs the PHP code and sends the output to the browser -> Option C

4. Quick Check:

   PHP runs on server = A [OK]

Hint: Remember: PHP runs on server, browser gets output only [OK]

Common Mistakes:

• Thinking browser executes PHP code
• Expecting PHP code to be visible in browser source
• Confusing PHP with client-side languages like JavaScript

2. Which of the following is the correct way to start a PHP block in a file?

easy

A.

B.

C.

D.

Solution

1. Step 1: Recall PHP opening tags

   The standard and recommended way to start PHP code is with

2. Step 2: Check each option

   uses which is correct. Others are invalid or incomplete tags.

3. Final Answer:

   -> Option A

4. Quick Check:

   Standard PHP tag = B [OK]

Hint: PHP code always starts with php [OK]

Common Mistakes:

• Using short tags like which may be disabled
• Confusing PHP tags with HTML or script tags
• Missing the 'php' keyword after

3. What will be the output of this PHP code when accessed via a browser?

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

medium

A. Syntax Error

B. echo "Hello, " . "world!";

C. Hello, . world!

D. Hello, world!

Solution

1. Step 1: Understand echo statement

   The echo command outputs the combined string "Hello, world!" to the browser.

2. Step 2: Confirm string concatenation

   The dot operator joins "Hello, " and "world!" correctly without errors.

3. Final Answer:

   Hello, world! -> Option D

4. Quick Check:

   echo concatenates strings = D [OK]

Hint: echo prints combined strings directly [OK]

Common Mistakes:

• Expecting PHP code to show in browser
• Confusing concatenation operator
• Thinking dot prints as text

4. Identify the error in this PHP code snippet:

<?php
echo "Welcome to PHP!"
?>

medium

A. Missing quotes around string

B. Missing semicolon after echo statement

C. Incorrect PHP opening tag

D. Using echo instead of print

Solution

1. Step 1: Check syntax of echo statement

   PHP statements must end with a semicolon ; to separate commands.

2. Step 2: Locate missing semicolon

   The echo line lacks a semicolon at the end, causing a syntax error.

3. Final Answer:

   Missing semicolon after echo statement -> Option B

4. Quick Check:

   Statements need ; = C [OK]

Hint: Always end PHP statements with a semicolon ; [OK]

Common Mistakes:

• Forgetting semicolon at line end
• Confusing PHP tags with HTML tags
• Assuming echo doesn't need semicolon

5. You want to create a PHP page that shows the current year dynamically. Which code snippet correctly does this?

<?php
// Options:
// A: echo date("Y");
// B: echo "date(Y)";
// C: echo date(Y, Y);
// D: echo "Y";
?>

hard

A. echo date("Y");

B. echo "date(Y)";

C. echo date(Y, Y);

D. echo "Y";

Solution

1. Step 1: Understand PHP date function usage

   The date function requires the format string in quotes to return the current year.

2. Step 2: Evaluate each option

   echo date("Y"); correctly calls date("Y") to output the year. echo "date(Y)"; prints the string literally. echo date(Y, Y); misses quotes causing undefined constants and wrong output (1970). echo "Y"; prints letter Y only.

3. Final Answer:

   echo date("Y"); -> Option A

4. Quick Check:

   Correct date format string = A [OK]

Hint: Use quotes around format in date() function [OK]

Common Mistakes:

• Omitting quotes around format string
• Printing function call as string
• Confusing output with literal text