Add a JS logic to validate the "creation/update form" of a book

[MarceStarlet]

Validate the data integrity from the form filled out by the user:

• All fields are required*
• ISBN must have 10 or 13 digit size.
  • Validate ISBN has only digits, not other characters.
• Edition must be a valid year between 1900 - Current year
• Should be filled at least one Author
  • Author's Name is required
  • Author's Biography is optional
• Should be filled at least one Classifcation

Add a new JS function to the booksearcher.js file or create a new file.
Display alerts for errors, and use input form CSS classes for required fields.

NOTE: This issue does only affect JS code and must be used in create & update views.

[C-Dumur]

I'am beginner In JS but I'll work on this