Best Graph Library :)
- SocialCompare has an extensive list of libraries, and the "Node / edge graph" line will filter for graph visualization ones.
- DataVisualization.ch has evaluated many libraries, including
node/graph ones. Unfortunately there's no direct link so you'll have to
filter for "graph":
- vis.js supports many types of network/edge graphs, plus timelines and 2D/3D charts. Auto-layout, auto-clustering, springy physics engine, mobile-friendly, keyboard navigation, hierarchical layout, animation etc. MIT licensed and developed by a Dutch firm specializing in research on self-organizing networks.
- Cytoscape.js - interactive graph analysis and visualization with mobile support, following jQuery conventions. Funded via NIH grants and developed by by @maxkfranz (see his answer below) with help from several universities and other organizations.
- D3.js Powerful multi-purpose JS visualization library, the successor of Protovis. See the force-directed graph example, and other graph examples in the gallery.
- Plotly's JS visualization library uses D3.js with JS, Python, R, and MATLAB bindings. See a nexworkx example in IPython here, human interaction example here, and JS Embed API.
- sigma.js Lightweight but powerful library for drawing graphs
- jsPlumb jQuery plug-in for creating interactive connected graphs
- Springy - a force-directed graph layout algorithm
- JS Graph It - drag'n'drop boxes connected by straight lines. Minimal auto-layout of the lines.
- RaphaelJS's Graffle - interactive graph example of a generic multi-purpose vector drawing library. RaphaelJS can't layout nodes automatically; you'll need another library for that.
- JointJS Core - David Durman's MPL-licensed open source diagramming library. It can be used to create either static diagrams or fully interactive diagramming tools and application builders. Works in browsers supporting SVG. Layout algorithms not-included in the core package
- GoJS Interactive graph drawing and layout library
- yFiles for HTML Commercial graph drawing and layout library
- mxGraph Commercial HTML 5 diagramming library with support for older browsers
- KeyLines Commercial JS network visualization toolkit
- data visualization software lab Commercial multi-purpose visualization library
- Cytoscape Web Embeddable JS Network viewer (no new features planned; succeeded by Cytoscape.js)
- Canviz JS renderer for Graphviz graphs. Abandoned in Sep 2013.
- arbor.js Sophisticated graphing with nice physics and eye-candy. Abandoned in May 2012. Several semi-maintained forks exist.
- jsdot Client side graph drawing application. Abandoned in 2011.
- Moo Wheel Interactive JS representation for connections and relations (2008)
- JSViz 2007-era graph visualization script