#java script function
function displayExams() {

var student = document.getElementById("STUDENT_NAME").value;

var exams=document.getElementById("EXAMS_APPEARED").value;

##</code><code>##

select style='$style_input' name='EXAMS_APPEARED' id='EXAMS_APPEARED' onClick=\"displayExams();\" >
<option value=''>--Select--</option>
";

my $ExamsCount=@ExamsAppeared;
for (my $j=0;$j<$ExamsCount;$j++)
{
$DisplayString=$DisplayString."<option value='$ExamsAppeared[$j]'>$ExamsAppeared[$j]</option>\n";
}

@ExamsAppeared = getdbresult();

sub getdbresult {   # for getting the db data

stmts...

}