title: For an interior DIV with a border, how do I scroll the DIV's contents, but keep border fixed?
body: <p>Let me begin with a jsFiddle:
     <a href="https://jsfiddle.net/johnlove/f14rjc9o/35/" rel="nofollow noreferrer">https://jsfiddle.net/johnlove/f14rjc9o/35/</a></p>
  
  <p>For an interior DIV with a border, I want to scroll the DIV's contents, but keep border fixed?</p>
  
  <p>The background centers on the ability to scroll an inner DIV using only the window scrollbar and <strong>not</strong> use <code>overflow-y</code>.</p>
  
  <p>When I scroll using window scrollbar, the inner DIV #scrollableContent does scroll ... <strong>but</strong> the text inside the css border leaks out!</p>
  
  <p>Here is a picture or 2 ... the 1st before using scrollbar ... the 2nd after using scrollbar ... as you can hopefully see, the text inside the red border goes outside the red border:</p>
  
  <p><a href="https://i.stack.imgur.com/WEZ0R.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/WEZ0R.png" alt="enter image description here"></a></p>
  
  <p><a href="https://i.stack.imgur.com/3lKMS.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/3lKMS.png" alt="enter image description here"></a></p>
  
  <p><strong>1) HTML</strong></p>
  
  <pre><code>&lt;!--
  BoltClock's code to scroll inner DIV using window's scrollbar
  --&gt;
  &lt;div id="overlayTop"    class="overlay"&gt;&lt;/div&gt;
  &lt;div id="overlayRight"  class="overlay"&gt;&lt;/div&gt;
  &lt;div id="overlayBottom" class="overlay"&gt;&lt;/div&gt;
  &lt;div id="overlayLeft"   class="overlay"&gt;&lt;/div&gt;
  
  &lt;div id="roundedCornersWrapper"&gt;
      &lt;div id="roundedCorners"&gt;
          &lt;div id="scrollableContent"&gt;
  &lt;p&gt;etc etc&lt;/p&gt;
  &lt;p&gt;etc etc&lt;/p&gt;
  &lt;p&gt;etc etc&lt;/p&gt;
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  &lt;p&gt;etc etc&lt;/p&gt;
          &lt;/div&gt;
      &lt;/div&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p><strong>2) CSS</strong></p>
  
  <p>First, the code for <code>.overlay</code>:</p>
  
  <pre><code>.overlay {
      position: fixed;
  }
  
  #overlayTop, #overlayBottom {
      height: 2.5em;
      width:  100%;
  }
  
  #overlayLeft, #overlayRight {
      height: 100%;
      width:  2.5em;
  }
  
  #overlayTop    { top:    0; }
  #overlayLeft   { left:   0; }
  #overlayRight  { right:  0; }
  #overlayBottom { bottom: 0; }
  </code></pre>
  
  <p>Now, the regular stuff ...</p>
  
  <pre><code>body, #roundedCornersWrapper, #roundedCorners, #scrollableContent {
      -webkit-box-sizing: border-box;
         -moz-box-sizing: border-box;
          -ms-box-sizing: border-box;
           -o-box-sizing: border-box;
              box-sizing: border-box;
  }
  
  body {
      background: darkgreen url(../pics/garlandBackground.gif);
  } 
  
  #roundedCornersWrapper {
      /*
          "padding" = width of .overlay "borders"
      */
      padding: 2.5em 2.5em;
  }
  
  #roundedCorners {
      background: white url(../pics/music_notes.gif);
  
      border-style:  solid;
      border-color:  red;
      border-radius: 1.25em;
      border-width:  .50em;
  }
  
  /*
      This is added white space inside of your .overlay "borders" + #roundedCorners.
      This separates the text etc. content from .overlay.
  */
  #scrollableContent {
      /*
          v = 0 makes up for leading and trailing &lt;p&gt; .. &lt;/p&gt; in text
      */
      padding: 0.0em 1.0em;   /* v,h */
  }
  
  /*
      BEGIN the magic needed to make the roundedBodyCorners fill the whole window
  */
  html, body {
      height: 100%;
  }
  
  #roundedCornersWrapper {
      height: 100%;
  }
  
  #roundedCorners {
      height: 100%;
  }
  
  #scrollableContent {
      height: 100%;
   /*
      overflow-y: auto;   // the whole! idea is to dump the interior scrollbar //
   */
  }
  /*
      END fill magic
  */
  
  /*
      Odds-and-Ends
  */
  #scrollableContent {
      font-size: 1.5em;   /* = 1.5 X 12px from html Selector */
  }
  </code></pre>