Set up the equation of the bezier curve and roughly trace it for three control points (1,1) (2,2) and (3,1). Take u = 0,¼,½,¾,1. code example
Example: mathematically create bezier curve javascript
var canvas = document.getElementById('canvas');
var ctx = canvas.getContext('2d');
ctx.beginPath();
ctx.moveTo(50,20);
ctx.bezierCurveTo(230, 30, 150, 60, 50, 100);
ctx.stroke();
ctx.fillStyle = 'blue';
ctx.fillRect(50, 20, 10, 10);
ctx.fillRect(50, 100, 10, 10);
ctx.fillStyle = 'red';
ctx.fillRect(230, 30, 10, 10);
ctx.fillRect(150, 60, 10, 10);