the variable $res stock just the last submit input clicked. it must stock all submit values which i clicked in.
<html>
<head></head>
<body>
<form method="post" action="">
<p><input type="text" name="textbox" size="13" readonly></p>
<p>
<input type="submit" name="one" value="1">
<input type="submit" name="one" value="2">
<input type="submit" name="one" value="3">
</p>
<p>
<input type="submit" name="one" value="4">
<input type="submit" name="one" value="5">
<input type="submit" name="one" value="6">
</p>
<p>
<input type="submit" name="one" value="7">
<input type="submit" name="one" value="8">
<input type="submit" name="one" value="9">
</p>
<p>
<input type="submit" name="operation" value="+">
<input type="submit" name="one" value="0">
<input type="submit" name="operation" value="-">
</p>
</form>
php code :
<?php
$res="";
if(isset($_POST['one']))
{
$val = $_POST['one'];
$res.=$val;
echo $res;
}
?>
</body>
</html>
concatenation doesn't work on input submit, $res stock just a value of one input.