A simple Chartable in PHP

<html>
<head><title>Entities</title>
<style type="text/css">
/* <![CDATA[ */
code { font-size: 40px; }
table { border-collapse: collapse; }
table, tr, td, th { border: 1px solid #ffffff; }
th, td { max-width: 64px; width: 64px; overflow: auto; text-align: center; }
th { font-size: 15px; height: 32px; }
td { font-size: 10px; height: 64px; }
.type_a { background-color: #cccccc; }
.type_b { background-color: #999999; }
.type_e { background-color: #ff0000; }
/* ]]> */
</style>
<body><table border="0" cellpadding="0" cellspacing="0">
<?php
$start = 8448;
$end = 8543;
$width = 9;

if(isset($_GET['start']) AND isset($_GET['end']) AND isset($_GET['width'])) {
    $start = (int)$_GET['start'];
    $end   = (int)$_GET['end'];
    $width = (int)$_GET['width'];
}

echo("<tr>");
for($i = 0; $i < $width; $i++) {
    $type = "e";
    if(($i % 2) == 0) {
        $type = "b";
    } else {
        $type = "a";
    }
    echo("<th class=\"type_".$type."\">Nr</th><th class=\"type_".$type."\">Val</th>");
}
echo("</tr>\n");
for($i = $start; $i <= $end; $i=$i+$width) {
    echo("<tr>");
    for($j = $i; $j < $i+$width; $j++) {
        $type = "e";
        if(($j % 2) == 0) {
            $type = "a";
        } else {
            $type = "b";
        }

        echo("<td class=\"type_".$type."\">&amp;#".$j.";</td><td class=\"type_".$type."\"><code>&#".$j."</code></td>");
    }
    echo("</tr>\n");
}
?>
</table></body>
</html>