Update free-programming-books-langs.md

Proposed by EbookFoundation#9828 issue
Added Javascript Notes for Professionals book in Javascript language section

Author: SahilChaudharii

Diff for: books/free-programming-books-langs.md

@@ -1180,6 +1180,7 @@ Books on general-purpose programming that don't focus on a specific language are
 * [Understanding JavaScript OOP](http://robotlolita.me/2011/10/09/understanding-javascript-oop.html) - Quil (HTML)
 * [Understanding the DOM — Document Object Model](https://www.digitalocean.com/community/books/understanding-the-dom-document-object-model-ebook) - Tania Rascia (PDF, EPUB)
 * [You Don't Know JS](https://github.com/getify/You-Dont-Know-JS) - Kyle Simpson (HTML, PDF, EPUB, MOBI)
+* [Javascript Notes for Professionals](https://www.dbooks.org/javascript-notes-for-professionals-1513/read/) 
 
 
 #### AngularJS