<?
$in = $_REQUEST[in];
if ( isset($in) )
{ $out = sqrt($in); }
else
{ $out = ""; }
?>
<html>
<body bgcolor="#fad888">
<center>
<form>
<input type="text" name="in" cols="7" value="<? echo $in;?>" />
<input type="submit" value="Find square root">
<input type="text" name="out" value="<? echo $out; ?>" cols="7" />
</center>
</form>
</body>
</html>