How do you draw a ellipse or oval on HTML5 canvas?

Use HTML5 canvas' bezierCurveTo method in JavaScript:

• Move to the top center of the ellipse (A₁).
• Draw a béizer curve to bottom center of the ellipse (A₂) with controls points at the right corners (C₁ and C₂).
• Draw a béizer curve back to top center of the ellipse (A₁)with controls points at the left corners (C₃ and C₄).

function drawEllipse(centerX, centerY, width, height) {
	
  context.beginPath();
  
  context.moveTo(centerX, centerY - height/2); // A1
  
  context.bezierCurveTo(
    centerX + width/2, centerY - height/2, // C1
    centerX + width/2, centerY + height/2, // C2
    centerX, centerY + height/2); // A2

  context.bezierCurveTo(
    centerX - width/2, centerY + height/2, // C3
    centerX - width/2, centerY - height/2, // C4
    centerX, centerY - height/2); // A1
 
  context.fillStyle = "red";
  context.fill();
  context.closePath();	
}