No it's not. Because JavaScript the language is so bare-bones, you need to supplement language deficiencies with frameworks and libraries. So you go and pick from a menu of Backbone/Marionette, Angular, ExtJS, Ember, Kendo, jQuery or etc. - some of them work together, some of them don't. Most of those get you part of the way there, you may still need to pull in things like require.js to manage imports. Or, instead of raw JS, you go with TypedScript, or Dart, or CoffeeScript, or whatever, and then put a framework on top of those. You're still not done, because that gets you the JS part, usually you complement it with a CSS framework (like bootstrap) and a SASS framework. In the end, you have a hodgepodge of frameworks of libraries, that plug JS holes, and functionally look and feel different.
So no, it's not simply JavaScript everywhere.