# Bounding box

The bounding box defines the viewport of the board, i.e. the portion of the $\mathbb{R}^2$ that is shown. The JavaScript code

var board = JXG.JSXGraph.initBoard('jxgbox', {boundingbox:[-5,10,5,-2], keepaspectratio: true, axis:true});

sets the vertical and horizontal units and the position of the origin such that the upper left corner of the drawing panel has position (-5,10) and the lower right corner of the drawing panel has position (5,-2).

The source code of the page looks like this: