spa/index.html

<!DOCTYPE html>
<html lang="en">
   <head>
      <meta charset="UTF-8">
      <meta name="viewport" content="width=device-width, initial-scale=1.0">
      <meta http-equiv="X-UA-Compatible" content="ie=edge">
      <link rel="stylesheet" href="css/bootstrap.css">
      <link rel="stylesheet" href="css/bootstrap-responsive.css">
      <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css">
      <script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.3.1/js/bootstrap.min.js"></script>
      <title>Document</title>
   </head>
   <style>
      .striked {
      text-decoration: line-through;
      }
   </style>
   <body>
     <div class="input-group mb-3">
      <input id="newTodo" class=class="custom-file-input" type="text" placeholder="Add new todo" style="margin-left:40%;margin-top:50px">
      <div class="input-group-append">
         <button id="btn1" class="btn btn-primary btn-sm" onclick="addTodo()" style="margin-top:50px"> ADD +</button>
      </div>
     
     </div> 
	  
      <table  style="margin-left:40%;margin-top:50px">
      </table>
	  
      <button class="btn btn-dark btn-sm"  onclick="removeStrike()"  style="margin-left:44%;margin-top:4%">BIN </button>
      <script>
          $("#newTodo").keyup(function(event) { 
            if (event.keyCode === 13) { 
                $("#btn1").click("addTodo()"); 
            } 
        }); 
      
      </script>
      <script src="https://code.jquery.com/jquery-3.4.1.min.js"></script>
      <script src="index.js" defer></script>
   </body>
</html>