W3Schools Tryit Editor

<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1">
<style>
body {
  font-family: Arial, Helvetica, sans-serif;
}

* {
  box-sizing: border-box;
}

/* Create a column layout with Flexbox */
.row {
  display: flex;
}

/* Left column (menu) */
.left {
  flex: 35%;
  padding: 15px 0;
}

.left h2 {
  padding-left: 8px;
}

/* Right column (page content) */
.right {
  flex: 65%;
  padding: 15px;
}

/* Style the search box */
#mySearch {
  width: 100%;
  font-size: 18px;
  padding: 11px;
  border: 1px solid #ddd;
}

/* Style the navigation menu inside the left column */
#myMenu {
  list-style-type: none;
  padding: 0;
  margin: 0;
}

#myMenu li a {
  padding: 12px;
  text-decoration: none;
  color: black;
  display: block
}

#myMenu li a:hover {
  background-color: #eee;
}
</style>
</head>
<body>

<h2>Search Menu</h2>
<p>Start to type for a specific category inside the search bar to "filter" the search options.</p>

<div class="row">
  <div class="left" style="background-color:#bbb;">
    <h2>Menu</h2>
    <input type="text" id="mySearch" onkeyup="myFunction()" placeholder="Search.." title="Type in a category">
    <ul id="myMenu">
      <li><a href="#">HTML</a></li>
      <li><a href="#">CSS</a></li>
      <li><a href="#">JavaScript</a></li>
      <li><a href="#">PHP</a></li>
      <li><a href="#">Python</a></li>
      <li><a href="#">jQuery</a></li>
      <li><a href="#">SQL</a></li>
      <li><a href="#">Bootstrap</a></li>
      <li><a href="#">Node.js</a></li>
    </ul>
  </div>
  
  <div class="right" style="background-color:#ddd;">
    <h2>Page Content</h2>
    <p>Start to type for a specific category inside the search bar to "filter" the search options.</p>
    <p>Some text..Some text..Some text..Some text..Some text..Some text..Some text..Some text..</p>
    <p>Some other text..Some text..Some text..Some text..Some text..Some text..Some text..Some text..</p>
    <p>Some text..</p>
  </div>
</div>

</body>
</html>

​x
 
<!DOCTYPE html><html><head><meta name="viewport" content="width=device-width, initial-scale=1"><style>body {  font-family: Arial, Helvetica, sans-serif;}​* {  box-sizing: border-box;}​/* Create a column layout with Flexbox */.row {  display: flex;}​/* Left column (menu) */.left {  flex: 35%;  padding: 15px 0;}​.left h2 {  padding-left: 8px;}​/* Right column (page content) */.right {  flex: 65%;  padding: 15px;}​/* Style the search box */#mySearch {  width: 100%;  font-size: 18px;  padding: 11px;  border: 1px solid #ddd;}​/* Style the navigation menu inside the left column */#myMenu {  list-style-type: none;  padding: 0;  margin: 0;