Top 40 PHP Interview Question And Answers

Safalta Expert Published by: Aryan Rana Updated Sun, 02 Oct 2022 11:36 PM IST


One of the most sought-after careers in web development is PHP development. These questions are designed to help you ace the interview and land the job. The questions have the highest possibility of appearing in interviews for a job in web design or development. They are carefully chosen with the questions that have the best chance of making an impression.

One of the most popular programming languages used for web development in PHP. In the field of web development, PHP programming is one of the most sought-after careers. Due to this, it is quite difficult to find work. In order to help you ace the interview and land the job, these PHP interview questions were carefully chosen with the questions that have the highest likelihood of appearing in interviews. Due to its ability to produce significant results with little code, PHP is ranked among the top languages. Throughout the last few years, the industry has demanded this level of efficiency. Now that they are aware of this, businesses all over the world are spending a sizeable sum of money to hire skilled PHP developers who can fill these roles and perform well. These top-core PHP interview questions and answers will give you the advantage you need to approach the questions strategically and respond to them succinctly.  If you are interested in Digital Marketing or Graphic Designing and want to learn these interesting courses then click on the links mentioned Digital Marketing Course and Graphic Designing course

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Top 40 Interview Question And Answers

1. What is the primary use of PHP?

There are many applications for PHP for developers. The following are some of the most popular ideas that PHP provides:
  • It is really simple to grant a website's necessary content-restricted access using PHP.
  • Users can access certain cookies and set them in accordance with their needs.
  • It is simple to do database manipulation operations like addition, deletion, and modification.
  • The employment of features involving file processing ideas, email integration, and form handling is widespread.
  • Users can open, read, write, and other system operations thanks to the system module.

2. Does PHP support case-sensitive scripting?

This has a yes and a no answer. While function names are not totally case sensitive in PHP, variables and their declaration are.

For instance, user-written functions in PHP can have their names defined in uppercase but subsequently be referred to in lowercase, and the function will still work as intended.

You must comprehend what PEAR is before moving on to the following PHP interview questions for beginners.

3. What does PEAR in PHP stand for?

PHP Extension and Application Repository is referred to as PEAR. All of the reusable PHP components are housed in one of the frameworks and acting repositories. It not only contains some of the PHP libraries but also gives you a straightforward interface to set up packages automatically.

4. How does a PHP script get run?

Using the command-line interface, PHP programmes are simple to run (CLI). This is how the syntax reads:

php filename.php

The filename in this context refers to the script file. Along with the filename, you also need the.php extension.

5. What kinds of variables are there in PHP?

The following list of PHP's eight main data types:
  • A named, sorted collection of data is called an array.
  • A logical value is a boolean (True or False)
  • Double: Numbers with floating points, like 5.1525
  • Whole numbers without a floating point represent integers.
  • An object is a class instance that includes data and functionalities.
  • A unique data type that only accepts the NULL data is NULL.
  • Special variables with references to outside resources are a resource.
  • A string is a collection of characters, such as "Hello, students!"

6. What guidelines should you adhere to while naming variables in PHP?

When naming a variable in PHP, you must adhere to two basic requirements. These are what they are:

All variables must start with a letter or an underscore.
You cannot use special characters like +, %, -, &, etc.

7. What distinguishes a PHP variable from other types of variables?

Some of the most crucial components of using variables in PHP are as follows:
  • Variables may be declared prior to being assigned a value.
  • The "=" operator is used to assign a value to a variable.
  • The $ (dollar) sign is used to identify each variable in PHP.
  • A variable's value is determined by the most recent value it has been given.
  • Variables in PHP are not inherent. There is no clear statement.
You must comprehend what NULL is in order to answer the next PHP interview question for beginners.

8. What in PHP is NULL?

In PHP, the special data type NULL is used to indicate the presence of solely the NULL value. It cannot have any other value assigned to it.

PHP allows for the declaration of NULL in one of two ways, as illustrated below:

$var = NULL:


$var = null;

In PHP, the two aforementioned syntaxes function correctly.

9. What definition does PHP give to constants?

Utilizing PHP's define() function makes defining constants simple. The values of the constants can be simply defined and obtained using this function.

Constants cannot be modified after definition, as the name implies. It is not necessary for them to begin with the standard $ sign as is done in PHP syntax.

10. What purpose does PHP's constant() function serve?

To get the predefined values from a constant variable, use the constant() function. It is particularly useful when you don't know the variable's name.

11. What kinds of constants are predefined in PHP?

The following are some of the most popular constants in PHP:
  • _METHOD_: Displays the class name
  • CLASS_: Provides the class name.
  • FUNCTION_: Indicates the function name.
  • LINE_: Indicates the working line number.
  • FILE_: Displays the file name and its path.

12. What exactly does "PHP escape" mean?

PHP escape is a way of informing the PHP parser that specific code components are not part of the PHP code. This offers the fundamental tools for setting apart a section of PHP code from the rest of the application.

13. How does PHP compare two objects?

The '==' operator, which is available in PHP, is used to compare two objects simultaneously. This is used to determine whether the objects under comparison share any properties or values.

If two objects are being compared and they both reference the same class, the "===" operator is also used to compare them.

The following PHP interview question requires you to comprehend a fundamental idea.

14. What do the PHP terms "break" and "continue" mean?

Break: When used in a looping construct, this statement ends the current iteration and instantly executes the next chunk of code outside the looping construct's block.

Continue: By using this statement, the current iteration of the loop will be skipped, and the subsequent iterations will be carried out until the looping construct is terminated.

15. Which PHP frameworks are some of the most well-liked ones?

PHP has a large number of frameworks that are well-known for their application. Here are a few examples:
  • CodeIgniter
  • CakePHP
  • Laravel
  • Zend
  • Phalcon
  • Yii 2

16. What purpose do PHP's final class and final method serve?

If the word "final" appears in a declaration, it means that other classes cannot override the current method. When it is necessary to build an immutable class, this is utilised.

It should be noted that properties cannot be made final. Only classes and methods have the ability to be final.

17. How do PHP and JavaScript interact?

PHP is a server-side scripting language, whereas JavaScript is a client-side programming language. PHP offers the ability to produce JavaScript variables, which can be simply run in the browser and allow variables to be passed to PHP using a straightforward URL.

18. Does PHP connect with HTML?

Yes, the interplay between HTML and PHP is what really defines PHP. PHP scripts can quickly transfer information around and generate HTML mode.

HTML is a client-side language, while PHP is a server-side language. The interaction fills in the gaps and makes the most of both languages.

19. How many different kinds of arrays does PHP support?

The three primary array types used in PHP are as follows.
  • Arrays with indexes: These are arrays with data in them. The storage and access of data are both linear.
  • Arrays with strings in them for element indexing are known as associative arrays.
  • Arrays with several dimensions and indexes are referred to as multidimensional arrays.

20. How does PHP's "foreach" loop operate?

In order to traverse and loop across the array data type, PHP uses the foreach statement, which is a looping construct. Foreach operates in a straightforward manner; pointers are increased and elements are allocated values with each iteration of the value. Until the array is finished, this operation is repeated.

21. Is PHP capable of setting an endless execution time?

By including the set time limit(0) function at the start of a script, it is possible to have an endless execution time in PHP.

If not at the start of the script, this can alternatively be run in the php.ini file.

22. What function do PHP's constructors and destructors serve?

Because they make it simple to pass arguments when building a new object, constructors are utilised in PHP. The variables for the particular object under consideration are initialised using this.

Methods for destroying an object are known as destroyers. Both of these are unique solutions that PHP offers that allow you to complete complicated processes in a single step.

23. Which of the most popular Content Management Systems (CMS) for PHP are you using?

Many different CMS is used with PHP. The following are the most well-liked:
  • WordPress
  • Joomla
  • Magneto
  • Drupal

24. What role do comments have in PHP?

In PHP, comments can be used in one of two ways. They come in both single-line and multi-line formats.

The traditional "#" sign can be used for single-line comments.


# This is a comment
echo "Single-line comment";
Multi-line comments can be denoted using ‘/* */’ in PHP.


This is
echo "Multi-line comment";

25. What is the most popular technique in PHP for hashing passwords?

For this purpose, the crypt() function is frequently used because it offers a huge selection of usable hashing algorithms. Md5, sha1, and sha256 are some of these algorithms.

26. In PHP, what do sessions and cookies mean?

In the architecture, sessions are global variables that are kept on the server. Each and every session is given a special server ID, which is used subsequently to handle value storage and retrieval.

In the architecture, cookies are entities that are used to identify particular users. The server inserts a tiny file into the client system. In order to develop various parts of the server, this is done in order to gather important information from the client.

27. Is PHP capable of typecasting?

Typecasting is provided by PHP and is relatively simple to do. The types that can be cast in PHP are as follows:
  • (int), (integer): Cast to integer
  • (bool), (boolean): Cast to boolean
  • (float), (double), (real): Cast to float
  • (string): Cast to string
  • (array): Cast to an array
  • (object): Cast to object

28. Is it possible to submit a form in PHP without using the submit button?

Yes, it is possible to submit a form without specifically pressing a button. The submit() method in JavaScript can be used to accomplish this quickly.

29. What kinds of PHP faults are there?

In PHP, there are three basic categories of errors. These are what they are:

An error that is not considered critical is given notice and is not shown to the user.
An error that is displayed to the user while the script is running is referred to as a warning.
The most serious kind of error is the fatal one. The script will end right away if there is a fatal error.

30. How does PHP receive the client's IP address?

Using the following syntax, a client who is connected can quickly get their IP address in PHP:


31. What purpose do PHP's $message and $$message serve?

PHP has two variables: $message and $$message. The name is what distinguishes them. Unlike $$message, which has a variable with a name that is actually saved in $message, $message has a fixed name.

Think about the following instance:

If 'var' makes up $message, then $$message is simply '$var.

32. Explain the differences between runtime exceptions and compile-time exceptions in PHP.

Compile-time exceptions are what they sound like: they happen when a script is being built, during the compilation process. A nice illustration of a compile-time exception is the FileNotFoundException.

A runtime exception is one that prevents the script from continuing to execute. An illustration of a runtime exception is the ArrayIndexOutOfBoundException.

33. What in PHP does type hinting mean?

In PHP, type hinting is employed when it is necessary to define the data type of an argument before passing it via a function.

The first time this method is used, PHP will quickly check to see if all the requested data types are present. If the result is different, the runtime will halt and an exception will be thrown.

34. How does PHP connect to a URL?

PHP may be simply connected to any URL by using the cURL library. With the normal PHP installation, this library is included.

Client-side URL, or "cURL," is a technology that enables users to access a URL and retrieve data from that page for display.

35. What are the procedures for building a new MySQL and PHP database?

To establish a new MySQL database in PHP, there are four fundamental stages. These are what they are:
  • The PHP script first establishes a connection to the MySQL server.
  • The connection is verified a second time. If the connection works, you can create a test query to make sure.
  • The database's creation queries are entered and then saved in a string variable.
  • The prepared queries are then carried out one by one.

36. Do you own any credentials that will strengthen your application for the position of PHP Developer?

The purpose of this inquiry is to determine whether you have any exposure to ongoing projects and practical experience. This is typically offered by a reputable certification school, and it conveys to the interviewer that you are committed to the career path you are pursuing. If you have any experience that is relevant, be sure to include what you learnt and used during the certification course.

37. How can we speed up the PHP script's execution?

  • The php.ini file specifies that a PHP script may run for a maximum of 30 seconds by default. It uses the set time limit function (int sec). It takes an infinite amount of time if the value passed is "0." It should be noted that the script will run for 45 seconds if the default timer is set to 30 seconds and a 20-second limit is provided in a set time limit().
  • You can extend this period by changing the max execution time in seconds. The time needs to be altered while still respecting the server's environment. This is due to the fact that altering the execution time will have an impact on every website the server hosts.
  • You can lengthen the script's execution duration by:
    Using the PHP script's sleep() function
    By means of the set time limit() function
The time frame is 30 seconds by default. To impose no time limit, the time limit might be set to zero.

38. Describe Zend Engine.

PHP utilises Zend Engine internally as a compiler and runtime engine. Zend OPCodes are created by compiling PHP scripts into memory.

Following the execution of these OPCodes, the client receives the HTML that was produced.

The Zend Engine manages resources, memory, and other standard services for the PHP programming language. The performance, dependability, and extensibility of PHP have contributed significantly to its rising popularity.

39. What library does PHP use for PDF?

Using PDFlib version 6, the PDF functions in PHP may produce PDF files. In addition to the function-oriented API for PHP4, PDFlib also provides an object-oriented API for PHP5.
The Panda module is another option.

FPDF is a PHP class that enables the creation of PDF files using only PHP (without using PDFlib). The F in FPDF stands for Free; we are free to use it for any purpose and alter it as necessary. With the exception of zlib to enable compression and GD to support GIF, FPDF works with both PHP4 and PHP5.

40. What brand-new features does PHP7 offer?

  • Performance enhancements for Zend Engine 3 and support for 64-bit integers on Windows
  • Compilation using a uniform variable syntax based on AST
  • Bitwise shift consistency across platforms was added to Closure::call() (Null coalesce) operator
  • Unicode escape code syntax
  • Return type statements
  • declarations of scalar types (integer, float, string, and boolean)


What is the primary purpose of PHP?

The most popular open source, the all-purpose server-side scripting language for developing dynamic websites and apps is PHP (short for Hypertext PreProcessor).

Why is PHP using echo?

Both of these are employed to display data on a screen. The changes are negligible: print can be used in expressions while echo does not, and print has a return value of 1. While print only needs one argument, echo can accept several parameters (although this usage is uncommon). Printing takes somewhat longer than expected.

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