Input into my textbox and on pressing go button, it enters info into another sites textbox AND pushes enter

Question

I'm a lil new with javascript and am not sure if this is what to use.

I would like to enter a case number into my site and when the user pushes go button, it goes to the www.uscis.gov site,enters the case number into the USCIS case status textbox, AND pushes the Go button.

OR

Is there an easier way to access their https://egov.uscis.gov/cris/caseStatusSearch.do