The best which i have got: Include in your js file and for including views you can add in this way
<!DOCTYPE html>_x000D_
<html lang="en">_x000D_
<head>_x000D_
<meta charset="utf-8">_x000D_
<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">_x000D_
<meta http-equiv="x-ua-compatible" content="ie=edge">_x000D_
<title>Bootstrap</title>_x000D_
<!-- Your custom styles (optional) -->_x000D_
<link href="css/style_different.css" rel="stylesheet">_x000D_
</head>_x000D_
_x000D_
<body>_x000D_
<script src="https://www.w3schools.com/lib/w3data.js"></script>_x000D_
<div class="">_x000D_
<div w3-include-html="templates/header.html"></div>_x000D_
<div w3-include-html="templates/dashboard.html"></div>_x000D_
<div w3-include-html="templates/footer.html"></div>_x000D_
</div>_x000D_
</body>_x000D_
<script type="text/javascript">_x000D_
w3IncludeHTML();_x000D_
</script>_x000D_
</html>
_x000D_