I’m sure you tried to export your Unity game to a WebGL version to publish it online. But it does not appear full screen.
Well, you can replace your index.html code with this, but do it at your own risk:
<!DOCTYPE html>
<html lang="en-us">
<head>
<meta charset="utf-8">
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>Unity WebGL Player | New Unity Project</title>
<link rel="shortcut icon" href="TemplateData/favicon.ico">
<link rel="stylesheet" href="TemplateData/style.css">
<script src="TemplateData/UnityProgress.js"></script>
<script src="Build/UnityLoader.js"></script>
<script>
var unityInstance = UnityLoader.instantiate("unityContainer", "Build/WebBuild.json", {onProgress: UnityProgress});
</script>
</head>
<body>
<div class="webgl-content" style="display: table; width: 100%; height: 100%;">
<div id="unityContainer"></div>
</div>
<script>
var mywidth = innerWidth;
var myheight = innerHeight;
document.getElementById("unityContainer").style.width = mywidth + "px";
document.getElementById("unityContainer").style.height = myheight + "px";
</script>
</body>
</html>
And, hey, don’t forget you need to change this “Build/WebBuild.json” according your project. In my case the json file name is WebBuild… For you, it can be anything.
Good luck!