Webgl library for CAD applications

I would like to create some simple CAD applications (web applications perfectly portable for mobile devices). For example, create a 2D floor tile layout. You need to enter precise measurements (floor dimensions, tile dimensions), create a tile layout grid, move the tile layout across the floor, etc.
Having done the layout, it would be nice to render it in 3D with texture. Learning 2D / 3D programming presents a pretty steep learning curve for me (judging from the tutorials I've seen), so I would like to start with what works best for the task.