How to clear a rectangle region on HTML5 canvas

Description

The clearRect(x, y, w, h) method clear what has been drawn in the specified rectangle.

x and y are the offset from the top-left corner of the canvas element. The w and h arguments specify the width and height of the rectangle.

Example


<!DOCTYPE HTML>
<html>
<head>
<style>
canvas {<!--   w  w w.ja  v  a2  s . c  o  m-->
      border: thin solid black;
      margin: 4px
}
</style>
</head>
<body>
      <canvas id="canvas" width="500" height="500"> 
    Your browser doesn't support the <code>canvas</code> element 
    </canvas>
      <script>
            var ctx = document.getElementById("canvas").getContext("2d");
            ctx.fillRect(10, 100, 100, 100);
            ctx.strokeRect(130, 130, 100, 100);
            ctx.clearRect(150, 150, 30, 10);}
      </script>
</body>
</html>