[galaxy-user] How to Pass Parameter

hi galaxy developers , i have developed this parameter in xml file and i am passing  "tl" value to a function which is present in my python file , but when i select its type=text , it shows a text field with  tl , all i want to know how can i pass kb value without showing text field on galaxy. thanks <param name="site" type="text" label="site for" value="tl" help="Enter tl "/>