function uuid() {     if (function_exists ( ‘com_create_guid’ )) {         return com_create_guid ();     } else {         mt_srand ( ( double ) microtime () * 10000 ); //optional for php 4.2.0 and up.随便数播种，4.2.0以后不需要了。         $charid = strtoupper ( md5 ( uniqid ( rand (), true ) ) ); //根据当前时间（微秒计）生成唯一id.         $hyphen = chr ( 45 ); // “-”         $uuid = ’’ . //chr(123)// “{” substr ( $charid, 0, 8 ) . $hyphen . substr ( $charid, 8, 4 ) . $hyphen . substr ( $charid, 12, 4 ) . $hyphen . substr ( $charid, 16, 4 ) . $hyphen . substr ( $charid, 20, 12 );         //.chr(125);// “}”         return $uuid;     } }