[galaxy-dev] Upload file button

Hi, I am creating a tool to convert format. The tool will read from the original file, convert the format, then output. Should I put a "Browser" button like the example tool "Get Data -> Upload File" or I should put a simple input textbox, let the user paste the input file path? You can see the original tool here: http://hiv-dev.lanl.gov:8081/content/sequence/FORMAT_CONVERSION/form.html Simply speaking, how can I implement the "Upload File" button. I try to add <param name="filePath" type="file" size="30" label="Or upload your file:" ajax-upload="true"/> to the xml file of the tool. The UI looks right, but when I click "execute", nothing happens. Thanks