A simple calculator
examples/intro/simple_calculator.php
<form method="GET"> <table> <tr><td>Value:</td><td><input name="a" ></td></tr> <tr><td>Value:</td><td><input name="b" ></td></tr> <tr><td></td><td><input type="submit" value="+"></td></tr> </table> <?php print "Result: $_GET[a]+$_GET[b]="; print $_GET[a] + $_GET[b]; ?>