How to draw the three triangle in single page using canvas?

Answer 1

function draw() {
  var canvas = document.getElementById('canvas');
  if (canvas.getContext){
    var ctx = canvas.getContext('2d');

    ctx.beginPath();
    ctx.moveTo(75,50);
    ctx.lineTo(100,75);
    ctx.lineTo(100,25);
    ctx.fill();
  }
}

You can reffer following artice-Drawing shapes in canvas.