1. If PHP Uploader detects SilverLight is installed on your PC, It will use the SilverLight solution.
2. If PHP Uploader detects Flash is installed on your PC, It will use the Flash solution.
3. If PHP Uploader detects Iframe is supported on your Browser, It will use the Iframe solution.
4. PHP Uploader will render as default php upload control.
If you want to select multiple files, please make sure you have installed silverlight or flash on your client computer.
Regards,
Eric