TreeGrid

dhtmlxTreeGrid is a special extension for dhtmlxGrid. This component allows showing the nested tabular data. Being a successor of Grid, TreeGrid inherits its API and common techniques of initialization and usage.
Check online samples for dhtmlxTreeGrid.

API Reference

dhtmlxGrid API

Related resources

To get just dhtmlxTreeGrid, download it from dhtmlx.com
To get the whole JavaScript library of UI components download dhtmlxSuite
There are also online samples for dhtmlxTreeGrid

Guides

Initialization
Configuration
Data Loading
Work with Grid
Customization
Event Handling

Says how to build a standard grid on a page and bring it to life: configure with specific settings, customize the default templates, attach events, etc.