HTML5 - Beginners - Swap Variables Destructuring.html

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width" />
</head>
<body bgcolor="black">
<div id="test"></div>
<canvas id="myCanvas" width="320" height="240" style="border:0px solid #d3d3d3;">
Use different browser.
</canvas>
	<script>
	var c=document.getElementById("myCanvas");
	var ctx=c.getContext("2d");

	// Destructing array
	// Swap variables
	// Set up variables.
	var [px,py,pw,ph] = [100,100,25,100];
	
	// Swap width and height.
	[pw,ph] = [ph,pw];

	//
	// Sometimes you want to swap two variables.
	// By using a destructuring array
	// you need no additional variables to do this.


	gameloop=setInterval(doGameLoop,16);

	function doGameLoop(){
		myCanvas.height = window.innerHeight-32;
		myCanvas.width = window.innerWidth-32;
		ctx.fillStyle="rgb(0,0,0)";
		ctx.fillRect(0,0,c.width,c.height);
		ctx.fillStyle="rgb(255,255,255)";
		ctx.fillText("Javascript Html canvas example.",10,10); 
		
		// Draw the player.
		ctx.fillStyle="white";
		ctx.fillRect(px,py,pw,ph);
	}
</script>
</body>
</html>