add viewport meta for mobile

based on unity's more recent minimal template; shared by mattia fortunati

WebGLTemplates/BetterMinimal/index.html

@@ -103,6 +103,14 @@
 			});
 			window.addEventListener('resize', onResize);
 			onResize();
+
+			if (/iPhone|iPad|iPod|Android/i.test(navigator.userAgent)) {
+				// Mobile device style: fill the whole browser client area with the game canvas:
+				const meta = document.createElement('meta');
+				meta.name = 'viewport';
+				meta.content = 'width=device-width, height=device-height, initial-scale=1.0, user-scalable=no, shrink-to-fit=yes';
+				document.getElementsByTagName('head')[0].appendChild(meta);
+			}
 		</script>
 	</div>
 </body>