Check out example codes for "html boilerplate". It will help you in understanding the concepts better.

Code Example 1

<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8" />
        <meta name="viewport" content="width=device-width, initial-scale=1.0" />

        <link rel="stylesheet" href="Index.css" />
        <title>Title</title>
    </head>
    <body>

        <header>
            <h1>>Header</h1>
        </header>

        <script src="Index.js"></script>
    </body>
</html>

Code Example 2

<!doctype html>

<html lang="en">
<head>
  <meta charset="utf-8">

  <title>Title here</title>

  <link rel="stylesheet" href="css/styles.css">

</head>

<body>
  <script src="js/scripts.js"></script>
</body>
</html>

Code Example 3

<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <link rel="stylesheet" href="Index.css">
        <title>Title</title>
    </head>
    <body>
        <script src="Index.js"></script>
    </body>
</html>

Code Example 4

//Simple Boilerpate

<html>
  <head>
    <title>yourtitle</title>
  </head>
  <body>
    //yourcontent
  </body>
</html>

Code Example 5

<!doctype html>

<!--language set to English-->
<html lang="en">
  <head>
    <meta charset="utf-8">

  	<title>Title here</title> <!--Title here-->

  	<link rel="stylesheet" href="css/styles.css">
  </head>
  <body>
    <!--your content here-->
  </body>
</html>

Code Example 6

<!-- HTML, CSS, JavaScript w/ jQuery -->
<!DOCTYPE html>
<html>
  <head>
    <meta charset="UTF-8">
    <title>title</title>
    <style>
      /* CSS */
    </style>
  </head>
  <body>
  <!-- HTML -->
  <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js" type="text/javascript"></script>
  <script>
    // JavaScript w/ jQuery
  </script>
  </body>
</html>

Code Example 7

<!DOCTYPE html>
<html>
  <head>
    <meta charset="UTF-8"> 
 <!--Add meta tag, Google Font cdn, bootstrap cdn here--> 
  </head>
  
  <body>
  <!--text, img, and structure here-->  
  <!-- Javascript & Jquary bootstrap cdn here-->
  </body>
</html>

Code Example 8

<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8" />
        <meta name="viewport" content="width=device-width, initial-scale=1.0" />
        <link rel="stylesheet" href="Index.css" />
        <title>Title</title>
    </head>
    <body>
        <script src="Index.js"></script>
    </body>
</html>

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