如何在JSXGraph中传递元素对象而不是id？

Question

I'm trying to change

var brd2 = JXG.JSXGraph.initBoard('box', {boundingbox: [-8.75, 2.5, 8.75, -2.5]});

as

var brd2 = JXG.JSXGraph.initBoard(this.$('#box'), {boundingbox: [-8.75, 2.5, 8.75, -2.5]});

Since dynamic elements are created inside backbone views, I need to initialize JSXGraph for each element with the id "box".

Answer 1

With the following hack it is possible to pass the object instead of the id to JSXGraph. First you need an invisible div with eg the id "dummy". Then the board is initialised with this dummy id and we have to make corrections afterwards. Let's further assume that

var board = JXG.JSXGraph.initBoard('dummy', {axis:false,
    boundingbox: [-10,30,10,-10], keepaspectratio:false});

var obj = document.getElementById('box'); // or this.$('#box')

board.removeEventHandlers();
board.container = 'box';
board.containerObj = obj;
//
// Supply the dimensions of the box
board.renderer = new JXG.SVGRenderer(obj, {width: 800, height: 800});
board.setBoundingBox([-10,30,10,-10], false);
board.addEventHandlers();

Please note, that specifying axis:true or grid:true in initBoard() will not work.

Hope that helps, Alfred