Line
From JSXGraph Wiki
Construction of a line
A line needs two points. Lets construct two points "A" and "B".
var b = JXG.JSXGraph.initBoard('jxgbox', {originX: 200, originY: 100, unitX: 50, unitY: 50});
var p1 = board.createElement('point',[-1,1], {name:'A',style:6});
var p2 = board.createElement('point',[2,-1], {name:'B',style:6});
Then we construct a line through "A" and "B". The setting of a new color and changing the stroke-width is not necessary.
var li = brd.createElement('line',["A","B"], {strokeColor:'#00ff00',strokeWidth:2});
Generally it is better to use JavaScript variables and not Geometry-Element names when constructing. Now, we do the same examples with JavaScript variables. Further, we don't show the whole line, but only a segment.
var li2 = brd2.createElement('line',[p1,p2], {straightFirst:false, straigtLast:false, strokeWidth:2});