Key Concepts

Review core concepts you need to learn to master this subject

Character Sets in Regular Expressions

Optional Quantifiers in Regular Expressions

Literals in Regular Expressions

Fixed Quantifiers in Regular Expressions

Alternation in Regular Expressions

Anchors in Regular Expressions

Regular Expressions

Wildcards in Regular expressions

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Character Sets in Regular Expressions

Regular expression character sets denoted by a pair of brackets [] will match any of the characters included within the brackets. For example, the regular expression con[sc]en[sc]us will match any of the spellings consensus, concensus, consencus, and concencus.

Introduction to Form Validation
Lesson 1 of 3
  1. 1
    Introduction
    Modern websites require a lot of information to function as intended. Information like our usernames, passwords, “friends”, “likes”, credit card information, and shopping orders all have to be prov…
    Start
  2. 2
    Why Validate Forms?
    Most data, once submitted, is stored by a website or web application. It’s stored in a database on the server side. There are important reasons for us to make sure the information that will be stor…
    Start
  3. 3
    Regular Expressions
    Data submitted through forms are stored as strings. Strings are a fundamental data type in computer science representing a series of characters “strung” together. As humans, we can intuitively reco…
    Start
  4. 4
    Client-side Validation: HTML
    The first technique we can use to validate form data is to prevent problematic inputs from being submitted in the first place. This is called client-side validation. The client is the process int…
    Start
  5. 5
    Client-side Validation: JavaScript
    Client-side validation has two main advantages. First, it’s a better experience for the user to be alerted to problematic data immediately rather than having to wait for that information to come ba…
    Start
  6. 6
    Back-end Validation
    No matter how complete the front-end validation of a website or application seems, validations must also be completed on the back-end or server-side. Front-end validations are easy to bypass—a mali…
    Start
  7. 7
    Review
    In this lesson, we’ve explored form validation from many angles. Let’s review what we covered: + Modern websites require a lot of information from their users and they collect a lot of this informa…
    Start

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