Key Concepts

Review core concepts you need to learn to master this subject

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
    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…
  2. 2
    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…
  3. 3
    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…
  4. 4
    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…
  5. 5
    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…
  6. 6
    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…
  7. 7
    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…

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