This article provides solutions for common issues you may encounter while working with the Kendo UI Upload widget.
- The Select button is partially visible and has no text
- Asynchronous uploads randomly fail
- The upload progress indicator incorrectly renders the progress of the upload
- The Upload demonstrates general performance issues
- Cannot access the error message console
The Kendo UI Upload uses an opacity filter to overlay the default Select button of the file input. This filter is implemented as an ActiveX control in Internet Explorer version 8 and earlier. As such, it is subject to security settings and can be disabled. The following image demonstrates an affected component.
Solution In Internet Explorer, set Internet Options > Security > Internet (or Local intranet) > Custom Level > Binary and script behaviors to Enable.
When working in Internet Explorer version 10 or 11 with Windows authentication, the upload freezes indefinitely or, if a 401 challenge is received on the HTTP POST, the upload times out.
When working in Internet Explorer version 10 or 11 with Windows authentication, the upload progress indicator can go over 100% or freeze but does not indicate that the request is complete. The issue is not related to Kendo UI and is caused by a bug in Internet Explorer which can be observed with any
FormData XMLHttpRequest. The problem seems to occur only when accessing a web server on
Solution Deploy the application on a remote web server or disable asynchronous uploads.
When working in Opera, the following symptoms of incorrect behavior occur:
successis fired when the file upload fails.
- The server response cannot be accessed in the
successevent 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
When a server error occurs, the complete server response is logged in the console. The console is accessible in a specific manner for each browser as listed below:
- Internet Explorer—Open the developer tools (
F12) and choose the Script tab. The console is visible on the right.
- Firefox—Install Firebug and enable the Console tab.
- Safari—Enable the Develop menu from the Preferences/Advanced dialog. Open the error console from the Develop menu.
- Any browser—Use a debugging proxy like Fiddler or Charles to obtain the server response.