Question:

I am trying to load a Excel file in Excel online.

By loading a file I mean lets say I receive an Excel file from a service which I need to show on the current workbook.

The file location can be a url or any folder in my site.

<pre class="lang-js prettyprint-override">Excel.run(function (context) { var workbook = context.workbook; //workbook.load or something ? }

Add-ins are scoped to the document and are intended to extend the functionality of the Office application, not as a mechanism for opening documents themselves.

What you're describing is what <a href="https://msdn.microsoft.com/en-us/library/hh622722%28v=office.12%29.aspx" rel="nofollow">WOPI</a> is intended for. The WOPI protocol provides an interface between Office and the document storage.

While you can implement your own WOPI client, it isn't a trivial process. A far simpler approach is to leverage the user's OneDrive via <a href="https://developer.microsoft.com/en-us/graph" rel="nofollow">Microsoft Graph</a>. Files stored in OneDrive include a <a href="https://developer.microsoft.com/en-us/graph/docs/api-reference/v1.0/resources/driveitem#properties" rel="nofollow">webUrl</a> property. If you open this URL it will automatically open the file in the correct application (Excel, Word, etc).

If you are looking to open an workbook through a link/path, that is not possible yet in the web add-ins as the scope of the add-in is limited to the workbook. It is something in our roadmap to support cross workbook scenario. If you are looking to embed the workbook in a browser, Marc's response has the answer (works for OneDrive, SharePoint only).