很棒的在线教学系统

												require_once 'HTMLPurifier/AttrTransform.php';								/**				 * Pre-transform that changes deprecated bgcolor attribute to CSS.				 */				class HTMLPurifier_AttrTransform_BgColor				extends HTMLPurifier_AttrTransform {								    function transform($attr, $config, &$context) {				        				        if (!isset($attr['bgcolor'])) return $attr;				        				        $bgcolor = $this->confiscateAttr($attr, 'bgcolor');				        // some validation should happen here				        				        $this->prependCSS($attr, "background-color:$bgcolor;");				        				        return $attr;				        				    }				    				}