How to add a lateral panel on the right of the screen that overlays the content of forms

Hi everyone,

On contact form I would like to add a lateral panel, on the right side of the form that overlays the form but can be hidden using Javascript. 

What I've tried to do is I've added a simple javascript method on the onload event of the form. The goal of the javascript method is to add a div on the right side of the form. As I want it to be displayed on top of everything, I've added a z-index property. The loaded div contains an iFrame that made some work and is printing staff in developer console. The result is that I get the logs printed in the console but the div colored in red that should be containing the iFrame is not displayed on top. It's hidden by the form.

Here is the simple javascript method (I've removed the source of the iFrame for confidential purpose):

function openIFrame() {   
	var iFrameUri = 'https://sourceOfIframe.com';
	var contentPanelDiv = '<div id="contentPanel" style='z-index: 10000;position: absolute;right: 0;top: 0;height: 100%;width: 200;position: fixed;background-color: #DE6161;margin: 0;'><iframe  allowTransparency='true' height='465px;' frameborder='0' scrolling='yes' src=''+ iFrameUri +'' type= 'text/javascript'></iframe></div>';
	document.body.innerHTML += contentPanelDiv;
}

Any idea how that company manages to do it: http://www.ingenius.com/microsoft-dynamics-crm/ 

Any idea how to achieve this ? 

Thanks in advance 
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