目录跳转到封页不动bug修复

bookdetail.html

@@ -588,7 +588,7 @@
 			//点击目录列表进行指定跳转
 			Dom.muluList.on("click", function (e) {
 				let cid = $(e.target).data('cid');
-				if (!cid) {
+				if (cid === undefined || cid === null || cid === "") {
 					return
 				}
 				Chapter_id = cid;