HTML5 Canvas not supported    

</canvas>    

<script>       

var canvas  = document.getElementById("ex4");    

var context = canvas.getContext("2d");    

var x = 10;    

var y = 10;    

var width = 100;    

var height = 100;    

context.lineWidth = 4;    

context.strokeRect(x, y, width, height);      

</script>