diff --git a/app/views/seminars/_contribute_form.html.erb b/app/views/seminars/_contribute_form.html.erb
index 4f0613d..b6e1f43 100644
--- a/app/views/seminars/_contribute_form.html.erb
+++ b/app/views/seminars/_contribute_form.html.erb
@@ -109,7 +109,7 @@
   $("form.form-horizontal").submit(function(){
     var flag = true;
     $("div[required=\"required\"]").each(function(i,v){
-      if($(v).find("input:checked").length == 0){
+      if($(v).find("input").length != 0 && $(v).find("input:checked").length == 0){
         $(v).find("input").attr("required","required");
         flag = false;
       }else{
@@ -121,11 +121,11 @@
   $("form.form-horizontal [type=\"submit\"]").click(function(){
     var flag = true;
     $("div[required=\"required\"]").each(function(i,v){
-      if($(v).find("input:checked").length == 0){
+      if($(v).find("input").length != 0 && $(v).find("input:checked").length == 0){
         $(v).find("input").attr("required","required");
         flag = false;
       }else{
-        $(v).find("input").removeAttr("required")
+        $(v).find("input").removeAttr("required");
       }
     })
     return flag;