Dynamically change variables in FORM whithout reload page

[norman29]

Hi all!
How can i do this:

[HTML]<form method="get" action="test.asp" >
<input name="boys" type=radio value="John">John
<input name="boys" type=radio value="Lu">Lu
<input name="boys" type=radio value="James">James
<input name="student" type=checkbox value="yes">student?
[/HTML]
and now: if student=yes then this boy is a student:

[HTML] <input type=hidden name="message1" value="he is a student">
<input type=hidden name="message2" value="welcome">
[/HTML]
or if student not "yes" then boy is not a student:

[HTML] <input type=hidden name="message1" value="who is it">
<input type=hidden name="message2" value="bye">

<input type="submit" value="Ок">
</form>[/html]

Thanks

[acoder]

Add an onclick to the checkbox to call a function:
[HTML]<input name="student" type=checkbox value="yes" onclick="isStudent(this)">student?[/HTML]
Add an id to the hidden field for easy access:[HTML] <input id="message1" type=hidden name="message1" value="he is a student">[/HTML]
and now onto the javascript:

function isStudent(checkbox) {
    var hidden = document.getElementById("message1");
    if (checkbox.checked) {
        hidden.value="this is a student";
    } else {
        hidden.value = "not a student";
    }
}