How To Show Only Page Content

Here is the script what i have

<script>
function showCustomer(str) {
var xhttp;
if (str == "") {
document.getElementById("txtHint").innerHTML = "";
return;
}
xhttp = new XMLHttpRequest();
xhttp.onreadystatechange = function() {
if (this.readyState == 4 && this.status == 200) {
document.getElementById("txtHint").innerHTML = this.responseText;
}
};
str = 49;
xhttp.open("GET", "http://www.abc.com/index.php?dispatch=pages.view&page_id="+str, true);
xhttp.send();
}
script>

here as the page link is given full page is opening on the same page.. but i want that only the page content of page id 49 should open.

What can i write so that i ll get only page content.

You can use the My changes module, create the pages.pre.php controller, use new mode (e.g. dispatch=pages.content) and output page content on this request

actually i want to show a page content of the page whose link is given in xhttp.open() on onchange dropdown list.

This is the full code
table,th,td {
border : 1px solid black;
border-collapse: collapse;
}
th,td {
padding: 5px;
}
Select a customer:
Alfreds Futterkiste
North/South
Wolski Zajazd

Customer info will be listed here...
i want to open the page in iframe.