Click the home page iframe repeat page-AdminLite

1. It is normal to initialize the home page for the first time, but there are duplicate pages (header area and left menu bar) when you click on the left menu bar-dashboard. How can you prevent repetition?

Please take a look at the following bug picture:

index.html

<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<head th:include="include/head :: css_head"></head>
<body class="hold-transition skin-blue sidebar-mini">
<div class="wrapper">
    <!--  -->
    <header th:include="include/header :: admin-header" class="main-header"></header>
    <!--  -->
    <aside th:include="include/left :: admin-left" class="main-sidebar"></aside>

    <!--  -->
    <div class="content-wrapper">
        <iframe name="mainFrame" id="mainBodyFrame" th:src="@{/include/main}" frameborder="0" scrolling="no" width="100%" style="min-height: 900px;" onload="resizeFrameHeight()"></iframe>
    </div>
    
  </body>
</html>

main.html

<!DOCTYPE html>
<html>
<head>
    <meta name="viewport" content="width=device-width" />
    <title></title>
</head>
<body>
<div>
    
</div>
</body>
</html>