Add a complete html to a div

You have to do it with a <iframe>

example:

<iframe id="Example2"
    name="Example2"
    title="Example2"
    width="400"
    height="300"
    frameborder="0"
    scrolling="no"
    marginheight="0"
    marginwidth="0"
    src="https://maps.google.com/maps?f=q&amp;source=s_q&amp;hl=es-419&amp;geocode=&amp;q=buenos+aires&amp;sll=37.0625,-95.677068&amp;sspn=38.638819,80.859375&amp;t=h&amp;ie=UTF8&amp;hq=&amp;hnear=Buenos+Aires,+Argentina&amp;z=11&amp;ll=-34.603723,-58.381593&amp;output=embed">
</iframe>

More data in MDN

You can use Javascript:

<script>
  document.getElementById("demo").innerHTML = "Hello <b>world</b>!";
</script>

or JQuery

$("button").click(function(){
  $("#demo").html("Hello <b>world</b>!");
});

You only need something that triggers that event, for example a click and you can change it every time the event is executed. Your div should have the ID "demo"

<div id="demo">
  ...
</div>

You can also do it with php using include:

<div id="demo">
  <?php
    include("ruta_del_html.htmlophp");
  ?>
</div>

I hope it serves you.

You can use AJAX to read the contents of the other HTML file and write it on your page:

var xmlhttp = new XMLHttpRequest();
xmlhttp.onreadystatechange = function() {
    if (xmlhttp.readyState == 4 && xmlhttp.status == 200) {
        document.getElementById("ID_OBJETIVO").innerHTML = xmlhttp.responseText;
    }
}
xmlhttp.open("GET", "URL_DEL_HTML_QUE_QUIERES_LEER", true);
xmlhttp.send();

Or if you use a library like jQuery, you can do something even simpler with features like $ .ajax () or $ .get () :

$.ajax({
    type: "GET",
    url: "URL_DEL_HTML_QUE_QUIERES_LEER",
    success: function(datos) {
        $("#ID_OBJETIVO").html(datos);
    }
})

If the content is a Web Page such as GoogleMaps, as Edgar says, you should use an iframe (which is no longer recommended to use). On the contrary, if the Html code is inside your site, or is a partrialView you can do it using Jquery.

function insertHtml(){
$("#htmlins").html("<span>este codigo html fue insertado</span>")
};

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

<div id="htmlins">
 </div>
<input type="button" value="Insertar Html" onclick="insertHtml()"/>