Get clientContext via Javascript from SharePoint 2013 external application (like a MVC4 application)

Hi,

I'd like to know if it’s possible for a SharePoint 2013 external application (like a MVC4 application) to get his clientContext via Javascript.

In fact, I know it’s possible to do that by CSOM via C# code but I use an ADFS, and I need to do that in JavaScript.

The reason for this request is that I need to dynamically create siteCollection from a MVC application. So I can do that using the webservice exposed by the central administration: /_vti_adm /Admin.asmx

But for this I give the password in clear text in my C# code.

Do you have any idea to proceed.

Thank you in advance

PS: sorry for my english