wget --post-data issue

["J. Bakshi" <bakshi12@gmail.com>]

Dear list,

I have a form which have 2 input field "Roll number" and "comments" ; using formfind command I get the following

```````````````````
--- FORM report. Uses POST to URL "index.php"
Input: NAME="go" VALUE="1" (HIDDEN)
Input: NAME="roll_no" VALUE="10" (TEXT)
Textarea: NAME="message"
Button: "Submit" (SUBMIT)
--- end of FORM
--- FORM report. Uses GET to URL "<form name=copy>"
Button: "Copy to clipboard" (BUTTON)
Textarea: NAME="txt"
--- end of FORM

````````````````````

The roll number always have 10 as default, and there is a text-area to input comment. How can I use wget with --post-data option to send the values ?
And how can I use wget for [ Button: "Submit" ] ?