I want to draw an image to the canvas on user click. My code works but only after the user clicks the button a second time after the page is first loaded. If you click twice then reload the page it will draw the image on the first click. If you them close all you browser windows then open the page again then you have to click twice again. I'm not sure what’s causing this behavior.

HTML Code:
<!DOCTYPE html>
		<script type="text/javascript">
			function draw_Domino(){
				var c=document.getElementById("myCanvas");
				var ctx=c.getContext("2d");
				var img2=new Image();

		<canvas id="myCanvas" width="600" height="600" style="border-style:solid;border-color:#B9D0D0;border-width:3px;">
			your browser does not support the canvas tag </canvas>
		<button onClick="draw_Domino()" style="height:50px;width:50px;background-color:green">Go</button>