Hi all, I am trying to format the input to a java tool that I am writing. I want to display different options to choose from based on the user input. I am not sure how to do that. For example, based on the input file, I want to display the chromosome options to choose from. How do I do this? <param name="input_bam_file" type="data" format="BAM" label="Input BAM file" help="Choose an input BAM file"/> <param name="chromosome_options" type="select" label="Choose the chromosome"> <option value="1"> chr1 </option> <option value="2"> chr2 </option> </param> I am not sure how to call a program that will generate the second input based on the first one and then wait for the user to choose the rest of the input and then run another program. I am a newbie. Any help is appreciated! Thanks, VJ.