little change on current person id cookie getting method

web/js/Project/project_display.js

@@ -2,8 +2,11 @@
 
 //全局变量：当前登录用户的id
 var strcookie = document.cookie;
+var userId = 0;
+if(strcookie.length > 0){
     var userIdStr = strcookie.split(";")[0];
-var userId = userIdStr.split("=")[1];
+    userId = userIdStr.split("=")[1];
+}
 
 //全局变量: 选中用户的id，可能为0
 var url = window.location.href;