How can I automatically submit a form?

I can submit a form without echoing that form. But how can the form be submitted after 5 minutes with the form being echoed?

Here is my code:

echo "<form name=myfm id=myfm1 method=post action=ats_exam.php>";
echo "<table width=100%> <tr> <td width=30>&nbsp;<td> <table border=0>";
$n=$_SESSION[qn]+1;
echo "<tR><td><span class=style2>Que ".  $n .": $row[2]</style>";
echo "<tr><td class=style6><input type=radio name=ans value=1>$row[3]";
echo "<tr><td class=style6> <input type=radio name=ans value=2>$row[4]";
echo "<tr><td class=style6><input type=radio name=ans value=3>$row[5]";
echo "<tr><td class=style6><input type=radio name=ans value=4>$row[6]";

if($_SESSION[qn]<mysql_num_rows($rs)-1)
echo "<tr><td><input type=submit name=submit1 value='Next Question'>      </form>";

echo "<tr><td><input type=submit name=submit value='Get Result'>

</form>";
echo "</table></table>";`