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Common Issues

The Select Button Is Partially Visible and Has No Text

The Kendo UI Upload widget uses an opacity filter to overlay the default file input's Select button. This filter is implemented as an ActiveX control in Internet Explorer 8 versions and older. As such, it is subject to security settings and can be disabled. Below is the sample image of an affected component:

Solution In Internet Explorer set the following option to Enable: Internet Options > Security > Internet (or Local intranet) > Custom Level > Binary and script behaviors.

Performance Issues

Asynchronous Uploads Randomly Fail

When working in Internet Explorer 10/11 with Windows authentication the upload either freezes indefinitely or times out if a 401 challenge is received on the HTTP POST.

Solution For Internet Explorer 10, see KB2980019. As of November 6, 2014 there is no official fix for Internet Explorer 11. For more information on this issue, refer to Bug ID 819941.

Incorrect Progress Readings

When working in Internet Explorer 10/11 with Windows authentication the upload progress indicator can go over 100% or freeze. This does not indicate that the request is now complete. The issue is not related to Kendo UI and is caused by an Internet Explorer bug. It can be observed with any FormData XMLHttpRequest. The problem only seems to occur when accessing a web server on localhost.

Solution Deploy the application on a remote web server or disable asynchronous uploads.

Incorrect Behavior

When working in Opera, the following symptoms, indicating 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 Opera Dragonfly. This debugging tool interferes with the upload by firing an extra Load event for the iframe.

Tips and Tricks

Access Error Message Consoles

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.
  • Chrome - open the JavaScript console (Ctrl+Shift+J).
  • 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.

See Also

Other articles on Kendo UI Upload:

Other articles on troubleshooting:

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