miterLimit : Maximum length of line join on a Canvas

lineJoin : Types of Line join

Change the miterLimit value by dragging the slider

for value less than 3 , the join type will be bevel.

gctx.miterLImit=3;

var my_canvas=$('#my_canvas').get(0)
var gctx = my_canvas.getContext("2d");
gctx.beginPath()
gctx.moveTo(100,280);
gctx.lineJoin = 'miter';
gctx.miterLimit=4;
gctx.lineTo(180,80);
gctx.lineTo(260,280);
gctx.strokeStyle= '#008cf5';
gctx.lineWidth =50;
gctx.stroke();