A Developer's Guide to the ISSN Validator

The ISSN Validator is a specialized tool for librarians, researchers, and publishers to verify the format and checksum of an International Standard Serial Number. ISSNs are 8-digit codes used to uniquely identify serial publications like magazines and journals.

Features

• Checksum Validation: The tool uses the standard modulo 11 algorithm to verify the 8th digit (the check digit), ensuring the ISSN is mathematically valid.
• Format-Agnostic Input: You can enter an ISSN with or without the hyphen; the tool will correctly parse it.
• Automatic Formatting: For a valid ISSN, the tool will display the correctly formatted version (e.g., 2049-3630).
• Clear Feedback: Get a simple "Valid" or "Invalid" result, along with a helpful message explaining the outcome.

How to Use

1. Enter the ISSN: Type or paste the 8-digit ISSN you want to check into the input field.
2. Click Validate: Press the "Validate" button.
3. Review the Result:
   • An alert will inform you if the ISSN is Valid or Invalid. If invalid, it will provide a reason (e.g., wrong length or failed checksum).
   • If the ISSN is valid, a card will appear showing the standard, hyphenated format.