$start= $_REQUEST['start'];
$end = $_GET['end'] - 1;
if (isset($_REQUEST['start']))
$start = $_REQUEST['start'];
else $start= '';
<?php
function get_value($haystack = [], $needle = [], $default = false)
{
foreach (!is_array($needle) ? [$needle] : $needle as $key) if (!empty($haystack[$key])) return $haystack[$key];
return $default;
}
$start = get_value($_REQUEST, 'start', null);
$end = get_value($_REQUEST, 'end', 1000);
$start= @$_REQUEST['start'];
$end = @$_GET['end'] - 1;