Added msg header 'text_length' property, which is usually the same as

'data_length', but not always (e.g. may include text from some header
fields, excludes any non-text data fields).
Mark 'data_length' msg header property as read-only.

src/sbbs3/js_msgbase.c

@@ -1362,7 +1362,8 @@ static JSBool js_get_msg_header_resolve(JSContext *cx, JSObject *obj, jsid id)
 	LAZY_UINTEGER("delivery_attempts", p->msg.hdr.delivery_attempts, JSPROP_ENUMERATE);
 	LAZY_UINTEGER("last_downloaded", p->msg.hdr.last_downloaded, JSPROP_ENUMERATE);
 	LAZY_UINTEGER("times_downloaded", p->msg.hdr.times_downloaded, JSPROP_ENUMERATE);
-	LAZY_UINTEGER("data_length", smb_getmsgdatlen(&(p->msg)), JSPROP_ENUMERATE);
+	LAZY_UINTEGER("data_length", smb_getmsgdatlen(&(p->msg)), JSPROP_ENUMERATE|JSPROP_READONLY);
+	LAZY_UINTEGER("text_length", smb_getmsgtxtlen(&(p->msg)), JSPROP_ENUMERATE|JSPROP_READONLY);
 	LAZY_STRING("date", msgdate((p->msg).hdr.when_written,date), JSPROP_ENUMERATE);
 	LAZY_UINTEGER("votes", p->msg.hdr.votes, JSPROP_ENUMERATE);