<script type="text/javascript"> function hello() { alert ("herro"); } </script> <form method="post" action=""> <input type="submit" name="submit" onclick="hello();" value="Submit"> </form> <?php if ($_POST['initialized']!=1) { echo "Initializing port<br>"; exec("echo 9 > /sys/class/gpio/export", $output, $return); exec("echo out > /sys/devices/virtual/gpio/gpio9/direction", $output, $return); } if ($_POST['led']==2) { echo "Led ON"; exec("echo 1 > /sys/devices/virtual/gpio/gpio9/value", $output, $return); } if ($_POST['led']==1) { echo "Led OFF"; exec("echo 0 > /sys/devices/virtual/gpio/gpio9/value", $output, $return); } ?> <form method="post"> <input type="hidden" name="led" value="2"> <input type="hidden" name="initialized" value="1"> <input type="submit" name="submit" value="Led ON"><br> </form> <form method="post"> <input type="hidden" name="led" value="1"> <input type="hidden" name="initialized" value="1"> <input type="submit" name="submit" value="Led OFF"><br> </form>