I came across a good website where a beginner can get a good content for Javascript before going for ServiceNow development.

https://www.codecademy.com/learn/introduction-to-javascript

Some of the part (projects and assignments) are paid one. But one can get these assignments and projects from the google too.

The answers for most these coding assignments are are available on this link :

https://github.com/kendalerishi/Code-Academy

If you feel this content and assignment solutions are useful for you. Please mark is as Helpful. Please pass-on the link to someone who is looking for JavaScript content.

Thank you,