Why .txt file in <iframe> is getting downloaded instead of displayed?

Question

I am using an <iframe> to display a text file:

<div class="document-view">
    <img src="img/302.GIF" />
</div> 

$(window).load(function () {
    <s:if test="extention.equalsIgnoreCase('txt')">
      element = '<iframe class="iframe" src="/dmsrepo/<s:property value="docLocation"/>" />';
    </s:if>

    $('.document-view').html(element);
});

When I inspect element in the browser I can see the file location.

<iframe class="iframe" src="/dmsrepo/Legal Doc Type/LegalDocType_123456789_1.0.txt" />

But the text file is getting downloaded in Chrome, Firefox and IE.

How to resolve this issue?

---

EDIT: you can reproduce the behavior in the following fiddle, that strangely affects only Firefox, for every page load after the first one.

Simply open the page, then press Run.

Note: it affects also the first load if Firebug Net module is activated.

Answer 1

because browser understands only html. Change your file extension to .html
or use server side language like php and using file_get_contents() function, you can display text file to browser.