General purpose library

• jQuery - http://jquery.com/
• Utility library
  • Lo-Dash - http://lodash.com/
  • UnderscoreJS - http://underscorejs.org/

MVC library

• BackboneJS - http://backbonejs.org/
• Layout manager (to support Backbone View) - https://github.com/tbranyen/backbone.layoutmanager/wiki
• Bootstrap - https://github.com/twitter/bootstrap/wiki
  • Bootstrap migration from 2.3.x to 3.x: http://bassjobsen.weblogs.fm/migrate-your-templates-from-twitter-bootstrap-2-x-to-twitter-bootstrap-3/

Graphics library (low level)

• Raphael - http://raphaeljs.com/
• D3.js - http://d3js.org/
• Arbor (a graph viz lib) - http://arborjs.org/
• VivaGraphJS - https://github.com/anvaka/VivaGraphJS
• DraculaJS - https://github.com/strathausen/dracula

Diagram Library

• JointJS - http://www.jointjs.com/
• jsPlumb - http://jsplumbtoolkit.com/jquery/demo.html
  • http://jsplumbtoolkit.com/jquery/flowchartConnectorsDemo.html

Misc Resources

• Building a UML editor in JavaScript - Part 1 
• Building a UML editor in JavaScript - Part 2 
• Building a UML editor in JavaScript - Part 3