wpdonate_4.php

<?php
public function __construct() {
	// register actions
	add_action( 'init', array( &$this, 'init' ) );
}

//Sanitizers
public function cplh_hexcolor_sanitize( $new_value, $old_value ) {
	$new_value = sanitize_hex_color( $new_value );
	return $new_value;
}
public function init() {
	add_filter( 'pre_update_option_cplh_highlight_color', array( &$this, 'cplh_hexcolor_sanitize' ), 10, 2 );
}

if ( ! function_exists( 'sanitize_hex_color' ) ) {
	function sanitize_hex_color( $color ) {
		if ( '' === $color )
			return '';

		// 3 or 6 hex digits, or the empty string.
		if ( preg_match('|^#([A-Fa-f0-9]{3}){1,2}$|', $color ) )
			return $color;

		return null;
	}
}