If you want to develop a UI for connecting elements like Workflow blocks indicating the flow or a flowchart which depicts an algorithm pictorially, jsPlumb is the right choice for you. This plugin is available also in MooTools and YUI3 (Yahoo User Interface 3) libraries apart from jQuery.
jsPlumb provides a means for a developer to visually connect elements on their web pages. It uses SVG or Canvas in modern browsers, and VML on IE 8 and below. The current version is 1.3.10.
jsPlumb has different kinds of connectors with bi-directional and uni-directional flowcharts which can be moved, re-connectable and removable at run-time. Here is a snap shot of State Machine Demo –
Demo: You can see jsPlumb in action here – DEMO
Download: jsPlumb can be download directly from here