patrickpelayo

A Responsive Iframe that will resize itself to its parent element.
<h4>Instructions</h4>
<h4>Install</h4>
The plugin manager is located on the administration page. From the administration page in the left side bar click Plugins. From the top of the page click add new.
Install the plugin thru the plugin manager, or upload it as a zip file into the plugin manager.
<h4>Use</h4>
<ul>
<li>
Apply responsive iframe 
Create a post like you normally would and then click the + icon displayed to Add block. Find Responsive iframes and click it. 
By default your current website will be displayed in the iframe.
</li>
<li>
Block Settings 
Site Address – The url address of the website you want to iframe 
Width – This represents the actual width you want to display from the iframed website. 
Height – This represents the actual height you want to display from the iframed website. 
Scrollbar – Displays a scroll bar if the height,and width are smaller than the iframe website. 
Border – Dislays a default border around the iframe element. 
Scale – This will change the max-width percentage of the iframe’s parent element, it will allow the element to be scaled by size. 
Additional CSS – Any additional CSS will be applied to the iframe’s parent element. Use this to provide some additional styling.
</li>
<li>
BreakPoints 
Available under advanced settings, and will let you specify the width of the site to display depending on the width of the device. 
Multiple breakpoints can be used. The lowest BreakPoint Width will take effect over any higher BreakPoint Widths when the screen device is below or at its BreakPoint Width. 
Example Breakpoint 1 250px, Breakpoint 2 350px. A device with a screen width of 250px will only trigger Breakpoint 1. ScreenWidth 251px, will only trigger BreakPoint 2. 
Name – The name you wish to give the breakpoint 
BreakPoint Width – At and below this width, this breakpoint is triggered. 
Site Width – This is the width of the website to display when the breakpoint is triggered
</li>
</ul>

Responsive iframe

Lets you place Iframes into your posts that will resize dynamically to maintain the same apperance.

Automattic

Donncha O Caoimh (a11n)

Michael Adams (mdawaffe)

Unfiltered MU gives Administrators and Editors the <code>unfiltered_html</code> capability. This prevents WordPress MU/WordPress 3.0 multisite from stripping <code><iframe></code>, <code><embed></code>, etc. from these users’ posts. Authors and Contributors do not get this capability for security reasons.
The plugin can either be used globally for your entire MU site, or it can be applied on a blog-by-blog basis.
For WordPress MU or WordPress 3.0 multisite only. Regular WordPress already offers this feature and does not need this plugin.
Warning! This is a very dangerous plugin to activate if you have untrusted users on your site. Any user could add Javascript code to steal the login cookies of any visitor who runs a blog on the same site. The rogue user can then inpersonate any of those users and wreak havoc. If all you want is to display videos on your WordPress MU blogs, use the native <a href="https://codex.wordpress.org/Embeds" rel="nofollow ugc">Embed Support</a>, <a href="https://wordpress.org/extend/plugins/vipers-video-quicktags/" rel="ugc">Viper’s Video Quicktags</a> or any of the other <a href="https://wordpress.org/extend/plugins/tags/video" rel="ugc">video plugins</a> on WordPress.org. 
If you use this plugin your site will be hacked in one way or another if you allow anonymous users on the Internet to create blogs on your site. It’s very dangerous.
Are you still 100% sure you want to use this plugin?

Unfiltered MU

I love when plugins are so cleanly written and do their trick without hassle. Especially after 8 years of no updates. Though they should submit an update just to remove the "2 years old" warning...

Still works! March 2017

This WordPress MU/WordPress 3.0 multisite plugin gives blog Administrators and Editors the ability to post whatever HTML they want.

Responsive iframe vs Unfiltered MU