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CanvasRenderingContext2D: drawFocusIfNeeded() method

Baseline Widely available *

This feature is well established and works across many devices and browser versions. It’s been available across browsers since ⁨August 2016⁩.

* Some parts of this feature may have varying levels of support.

The CanvasRenderingContext2D.drawFocusIfNeeded() method of the Canvas 2D API draws a focus ring around the current or given path, if the specified element is focused.

Syntax

drawFocusIfNeeded(element)
drawFocusIfNeeded(path, element)

Parameters

element: The element to check whether it is focused or not.
path: A Path2D path to use.

Return value

None (undefined).

Examples

Managing button focus

This example draws two buttons on a canvas. The drawFocusIfNeeded() method is used to draw a focus ring when appropriate.

HTML

<canvas id="canvas">
  <button id="button1">Continue</button>
  <button id="button2">Quit</button>
</canvas>

JavaScript

const canvas = document.getElementById("canvas");
const ctx = canvas.getContext("2d");
const button1 = document.getElementById("button1");
const button2 = document.getElementById("button2");

document.addEventListener("focus", redraw, true);
document.addEventListener("blur", redraw, true);
canvas.addEventListener("click", handleClick, false);
redraw();

function redraw() {
  ctx.clearRect(0, 0, canvas.width, canvas.height);
  drawButton(button1, 20, 20);
  drawButton(button2, 20, 80);
}

function handleClick(e) {
  // Calculate click coordinates
  const x = e.clientX - canvas.offsetLeft;
  const y = e.clientY - canvas.offsetTop;

  // Focus button1, if appropriate
  drawButton(button1, 20, 20);
  if (ctx.isPointInPath(x, y)) {
    button1.focus();
  }

  // Focus button2, if appropriate
  drawButton(button2, 20, 80);
  if (ctx.isPointInPath(x, y)) {
    button2.focus();
  }
}

function drawButton(el, x, y) {
  const active = document.activeElement === el;
  const width = 150;
  const height = 40;

  // Button background
  ctx.fillStyle = active ? "pink" : "lightgray";
  ctx.fillRect(x, y, width, height);

  // Button text
  ctx.font = "15px sans-serif";
  ctx.textAlign = "center";
  ctx.textBaseline = "middle";
  ctx.fillStyle = active ? "blue" : "black";
  ctx.fillText(el.textContent, x + width / 2, y + height / 2);

  // Define clickable area
  ctx.beginPath();
  ctx.rect(x, y, width, height);

  // Draw focus ring, if appropriate
  ctx.drawFocusIfNeeded(el);
}

Result

Specifications

Specification
HTML> # dom-context-2d-drawfocusifneeded-dev>

Browser compatibility

	Desktop					Mobile
	Chrome	Edge	Firefox	Opera	Safari	Chrome Android	Firefox for Android	Opera Android	Safari on IOS	Samsung Internet	WebView Android	WebView on iOS
`drawFocusIfNeeded`	37	14	3228	24	8	37	3228	24	8	3.0	37	8
`path_parameter`	37	14	No	24	8	37	No	24	8	3.0	37	8