// Prepare checkbox value which will be used in SQL statement.
// In this function, we add all the numbers in $checkboxlist parameter.
// If $checkboxlist is empty, then we return 0.
//
// Arguments:
// checkboxlist ; the value of CHECKBOXLIST parameter in the GetPOI request.
//
// Returns:
// checkbox_value ; the value that can be used to construct the right
// SQL statement.

function GetCheckboxValue ( $checkboxlist ) {
	// if $checkboxlist exists, prepare checkbox_value.
	if( isset( $checkboxlist ) ) {
	// Initialize returned value to be 0 if $checkboxlist is empty.
	$checkbox_value = 0;
	// If $checkboxlist is not empty, return the added value of all
	// the numbers splited by ‘,’.

	if (!empty($checkboxlist)) {
		if ( strstr($checkboxlist,’,’) ) {
			$checkbox_array = explode(‘,’, $checkboxlist);
				for( $i=0; $i<count($checkbox_array); $i++ )
			$checkbox_value+=$checkbox_array[$i];
		}//if
	else
		$checkbox_value = $checkboxlist;
	}//if
	return $checkbox_value;
	} //if
	else {
	throw new Exception(“checkboxlist parameter is not passed in GetPOI request.”);
	}//else
}//GetCheckboxValueCustom Slider Filter