diff --git a/ws/client.go b/ws/client.go
index 999555b..7a42604 100644
--- a/ws/client.go
+++ b/ws/client.go
@@ -156,12 +156,14 @@ func clientReader(c *client){
 
 		/* (4) CLOSE */
 		if msg.Type == CLOSE {
-			// fmt.Printf(" [reader] CLOSE ; size %d\n", msg.Size)
-			// if msg.Size >= 2 {
-			// 	errCode := binary.BigEndian.Uint16(msg.Data[0:2])
-			// 	fmt.Printf("                ; status %d\n", errCode)
-			// 	fmt.Printf("                ; msg '%s'\n", msg.Data[2:])
-			// }
+			// uncomplete code || too long
+			if msg.Size == 1 || msg.Size > 125 {
+				errorCode = PROTOCOL_ERR
+			}
+			// invalid utf-8 reason
+			if msg.Size > 2 && !utf8.Valid(msg.Data[2:]) {
+				errorCode = INVALID_PAYLOAD
+			}
 			clientAck = false
 			break