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13. JS Forms

Module 1 · Media Course's Objectives
Module 2 · Media Forms
Module 3 · Media Reset and Submit
Module 4 · Media Input Attributes
Module 5 · Media Validate a basic form
Module 6 · Media Checkvalidity
Module 7 · Media Invalid Event
Module 8 · Media Validity
Module 9 · Media Custom error messages
Module 10 · Media Form Pseudos
Module 11 · Media Validate the cv App
Module 12 · Media Validating string
Module 13 · Media Regex
Module 14 · Media The telephone number pattern
Module 15 · Media Literal
Module 16 · Media Alternatives Regex
Module 17 · Media Alternatives and optionals You are here
Module 18 · Media The Mohammed's Name problem
Module 19 · Media Metacharacters
Module 20 · Media Character Sets
Module 21 · Media Quantifiers
Module 22 · Media Full name regex problem
Module 23 · Media Validate Password pattern
Module 24 · Media Validate German cellphone number
Module 25 · Media Validate email address
Module 26 · Media Check Valid Url address
Module 27 · Media Boundary
Module 28 · Media Who loves bears?
Module 29 · Media Match
Module 30 · Media Modifiers
Module 31 · Media Facebook vs Twitter
Module 32 · Media The Pattern attribute
Module 33 · Media Form Attributes

Close the course

Module 17 of 33 · Media

Alternatives and optionals

Kostas Diakogiannis

Alternatives and optionals

With a ? question mark, we can specify that a part of the string is optional and could be additionally accepted if there, but not mandatory.

The main difference between optionals and alternatives is that optionals mean, that either this character will be put or nothing, alternatives in contrast mean either the one, or the other one. But in the end for sure something. Nothing is not an option.

If we don't want to have partial match we can specify that the string that we are testing on should should begin and end with the pattern we have, and it is not a subset of a bigger string. To specify that this is the beginning we do it with the ^ character, and the end with a $ dollar sign character.

Alternatives and optionals

13. JS Forms

Instructions

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