If you're delving into this book, it's clear that crafting efficient and universally compatible JavaScript code is no straightforward task. Beyond the usual hurdles of developing clear and maintainable code, we face the added intricacies of navigating the murky waters of browser inconsistencies. To navigate these challenges, JavaScript developers often encapsulate frequently used and reusable code snippets into JavaScript libraries. Despite their differences in strategy, scope, and complexity, these libraries share a few critical requirements: they must be user-friendly, lightweight, and compatible with all targeted browsers.