Upload Demonstrates General Performance Issues

Updated on Dec 10, 2025

Environment

Product	Progress® Kendo UI® Upload for jQuery
Operating System	Windows 10 64bit

Description

The jQuery Upload demonstrates general performance issues.

Cause

When working in Opera, the following symptoms of incorrect behavior occur:

• The success is fired when the file upload fails.
• The server response cannot be accessed in the success event.
• The success event fires before the upload is complete.

Solution

Turn off the Opera Dragonfly debugging tool because it interferes with the upload by firing an extra Load event for the iframe.

See Also

• JavaScript API Reference of the Upload