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Article ID: NDZ1264 — Created: 25 Jul 2019 — Reviewed: 12 Oct 2020
I have copied a deep zoom image (Deepzoom-unfiltered folder) to a shared folder on my network. I'm attempting to open the MIDZ.HTML file with my web browser but the browser window is blank and my scanned slide image does not display. What am I doing wrong?
There are only a few reasons why the MIDZ.HTML file does not open the Deepzoom Viewer when run directly.
There are a few things to check to make sure the folder contents were properly copied.
CORS (Cross-Origin Resource Sharing) is a security mechanism that web browsers use to allow access to restricted content from another domain. The Deep Zoom Viewer (MIDZ.HTML) performs AJAX requests to read the XML data for each deep zoom image. Some web browsers (most as of 2019) restrict that operation when the data is located on a local (or network) disk. When restricted, the web browser displays a blank screen for the deep zoom image.
For all other web browsers, you must explicitly give the browser permission to read the XML and image files for the deep zoom image.
You can disable the CORS file restriction only on the command line. For example:
You can also add the --allow-file-access-from-files argument to the Properties - Target command line. However, there are several Chrome plug-ins that should work.
The only way we found to disable CORS restrictions were with one of the Opera plug-ins that are available.
The latest version of Edge (v86...) is based on Chrome. The CORS file restriction can be disabled on the command line. For example:
You can also add the --allow-file-access-from-files argument to the Properties - Target command line just like under Chrome.
CORS restrictions are not a problem for deep zoom images served from a web site if the MIDZ.HTML file, XML files, and image files are all served from the same domain.