JavaScript Regular Expressions: The Animated Guide (2025)

About JavaScript Regular Expressions: The Animated Guide (2025)

Build Your Own Client-Side Validation System?

You'll do it.

Animated Explainer Videos To Learn Regular Expression concepts?

It's here!

This is the most interactive course online for mastering Regular Expressions In JavaScript with tips & tricks, visual illustrations,

and a lot of

animated explainer videos.

When you begin to learn

Regular Expressions

for the first time, it might seem like a random string of nonsense. While they might look awkward at times, they are very useful. Once you have a solid understanding of regular expressions you will become a much more effective programmer. To fully understand regular expressions you need to learn the basic concepts which you can build upon.

1. So What Is A Regular Expression?

A

regular expression

,

regex

or

regexp

(sometimes called a

rational expression

) is a way to describe a

_pattern_

to work with strings by using

special syntax

. By formulating a regular expression you can...

_Search for text in a string_ ,

_Replace a sub-string in a string_ ,

_Extract information from a string_.

2. A Little History About Regular Expressions.

Regular Expressions began to emerge as a way to describe regular languages. In the 1950s, Regular expressions originated when mathematician

Stephen Cole Kleene

described regular languages by using his mathematical notation called _regular sets_. Regular expressions later became an important part of the tool suite that emerged from the Unix operating system—the _ed_ , _sed_ and _vi_ (_vim_) editors, _grep_ , _AWK_ , among others. But the ways in which regular expressions were implemented were not always so regular. They really began to show up in the programming world during the 1970s. A variety of programming languages like: C#, C, C++, VB. NET, VB 6, Delphi, Java, Groovy, Perl, PHP, JavaScript, VBScript, Python, Go, Ruby, Tcl, PowerShell, R, and more support Regex very well.

3. Situations Where Regex Can Be Used.

Common applications include

data validation

,

data scraping

(especially web scraping),

data wrangling

,

simple parsing

,

syntax highlighting systems

, text or string processing tasks where the data need not be textual, and in

search engines

such as

Google

in order to determine an algorithmic match to the query a user is asking. Now have you ever wondered how you get feedback from an online form informing you that you had entered invalid information? How did it know you entered invalid information? The answer is that behind the scenes Regular Expressions is used to validate your input. Almost every programming language implements regular expressions. JavaScript is one of the programming languages with regular expressions support directly built-in. Since you can also run

JavaScript

on the server with

Node.js

, the Regular Expression Concepts In JavaScript is the same as

Regular Expressions In Node.js

4. What You Will Learn In This Course

This course aims to introduce you to JavaScript Regular Expressions in a simple way by using

annotations, tips & tricks, images,

and a lot of

animated

explainer videos. Here is exactly what you're going to learn:

Difference Between A Character And A String.

How To Match Simple Specific Characters.

How To Match Different Characters In A Single Position - Character Sets.

How To Define A Character Range To Match Different Characters In A Single Position - Character Ranges.

How To Define A Negated Character Set OR Range.

How To Match Any Character With A Period Or Dot (Except For A New Line).

How To Escape (Turn OFF Special Meaning) Reserved Regular Expression Characters By Using The Backslash "\" Character.

How To Match Any Word Character (Alphanumeric).

How To Match Any Non-Word Character.

How To Match Any Digit.

How To Match Any Non-Digit.

How To Match A Character Either Zero OR One Time.

How To Match Either Zero OR More Repetitions Of A Character.

How To Match Either One OR More Repetitions Of A Character.

Line Anchors - Assert The Start And The End Of A String.

How To Specify The Exact Amount Of Repetitions To Match.

How To Specify The Least (Minimum) Amount Of Repetitions To Match.

How To Specify The Minimum And Maximum Amount Of Repetitions To Match.

How To Match Alternate Strings OR Words.

How To Create Regular Expressions In JavaScript.

JavaScript Regular Expression Flags.

JavaScript Regular Expressions Methods.

Validating A Username By Using Regular Expressions And JavaScript.

Validating A Password By Using Regular Expressions And JavaScript.

Validating An Email By Using Regular Expressions And JavaScript. You will also get some practice using regular expressions, and then you will use all that you've learned to build a dynamic

Client-Side Form Validation System

that uses Regular Expressions And JavaScript to validate the data typed in. By the end of this course, you will gain valuable information to read and create your own regular expressions.

I learned Regular Expressions years ago by hard trial-and-error. Now you can learn at 5x the speed I did. This is the course that I wish I had when I first got started with Regular Expressions.

Now, I hope to welcome you as a new student in this course! So click that "Enroll" button right now, and join me in this adventure today

of learning

Regular Expressions

in

JavaScript!

But if you're not 100% sure yet, just go ahead and watch the promo video and free lectures to take a look at the course project. I promise you will be amazed :)

See you in the course!