I’ll just cut to the chase.

/**
 * create an array of all dates between two specified dates
 * @param datetime $strDateFrom
 * @param datetime $strDateTo
 * @return array
 */
function createDateRangeArray($strDateFrom, $strDateTo) {		
	$aryRange = array();
	$iDateFrom = mktime(1, 0, 0, substr($strDateFrom, 5, 2), substr($strDateFrom, 8, 2), substr($strDateFrom, 0, 4));
	$iDateTo = mktime(1, 0, 0, substr($strDateTo, 5, 2), substr($strDateTo, 8, 2), substr($strDateTo, 0, 4));
	if ($iDateTo >= $iDateFrom) {
		array_push($aryRange, date("Y-m-d", $iDateFrom));			
		while ($iDateFrom < $iDateTo) {
			$iDateFrom = $iDateFrom + 86400;
			array_push($aryRange, date("Y-m-d", $iDateFrom));
		}
	}
	return $aryRange;
}

If your users link to some URL, it’s always nice to check if their input actually represents a valid URL. You can do just that with this function:

/**
 * return true if the passed variable is a valid URL address
 * @param $url
 * @return boolean
 */
function isValidURL($url) {
	$pattern  = '/^(([\w]+:)?\/\/)?(([\d\w]|%[a-fA-f\d]{2,2})+(:([\d\w]|%[a-fA-f\d]{2,2})+)?@)?([\d\w][-\d\w]{0,253}[\d\w]\.)+[\w]{2,4}(:[\d]+)?(\/([-+_~.\d\w]|%[a-fA-f\d]{2,2})*)*(\?(&?([-+_~.\d\w]|%[a-fA-f\d]{2,2})=?)*)?(#([-+_~.\d\w]|%[a-fA-f\d]{2,2})*)?$/';
	return preg_match($pattern, $url);
}

If this function returns true, you might want to actually open the URL (using file_get_contents() or some other function) to see if it works.