How to create Salesforce visualforce page with iframe with auto resizing height?

Hi Tanu,

You can resize the iframe with JavaScript after you know the size of the browser viewport:

<apex:page sidebar="false">
<apex:iframe src="https://www.salesforce.com/" id="theFrame" />
<script>document.getElementById('theFrame').height = window.innerHeight - 220;</script>
</apex:page>

Leave about 220 pixels for the Salesforce header and footer.

Hope this helps you.

Thanks