<head>
  <meta charset="utf-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1">

  <title>{% if page.title %}{{ page.title }}{% else %}{{ site.title }}{% endif %}</title>
  <meta name="description" content="{% if page.excerpt %}{{ page.excerpt | strip_html | strip_newlines | truncate: 160 }}{% else %}{{ site.description }}{% endif %}">

  <link rel="stylesheet" href="{{ "/css/main.css" | prepend: site.baseurl }}">
  <link rel="canonical" href="{{ page.url | replace:'index.html','' | prepend: site.baseurl | prepend: site.url }}">
</head>

<head>
  <meta charset="utf-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1">

  <title>{% if page.title %}{{ page.title }}{% else %}{{ site.title }}{% endif %}</title>
  <meta name="description" content="{% if page.excerpt %}{{ page.excerpt | strip_html | strip_newlines | truncate: 160 }}{% else %}{{ site.description }}{% endif %}">

  <link rel="stylesheet" href="{{ "/css/main.css" | prepend: site.baseurl }}">

  <link rel="canonical" href="{{ page.url | replace:'index.html','' | prepend: site.baseurl | prepend: site.url }}">
  <script src="{{'/js/jquery/jquery.min.js' | prepend: site.baseurl}}"></script>
  <script src="{{'/js/bootstrap/bootstrap.min.js' | prepend: site.baseurl}}"></script>
 
</head>

Update Header with BootstrapJS and Jquery
Update Header with BootstrapJS and Jquery
