Hi!
Web development has 3 major parts - Front end, Backend and Database.
FrontEnd : for frontend you can start with brushing up HTML,CSS,Javascript and then you can move on to frameworks like ReactJS, AngularJS , VueJS but ReactJS is recommended framework(React is library literally speaking but is often called framework) as it has great learning curve and easy to grow.
Backend: For backend you can go through frameworks like Nodejs(Javascript), Django(python),PHP etc. As you said that you know javascript so Nodejs is recommended and it also has large community for grow.
DataBases:
Realtional or Non-relational Databases:
In Relational DBs data is stored in form of relations(tables) whereas in Non-relational DBs data is stored in objects with key-value pairs.
Some of famous DBs:
Relational:
Mysql,Oracle,Microsoft sql,Postgre sql etc,
Non-relational:
MongoDB,Apache Cassandra,Google Cloud BigTable,Apache HBase etc.
recommended DB is MongoDB(Non-relational).
If you are a beginner then follow recommended technologies. They have large community of developers. If you want to become a good developer then you may need to learn alternative techs depending on your project requirements. But if you are beginner and have no idea of them then you should start with the recommended techs.