perbaiki conflict script file size dan preview

opensipkd/base/views/widgets/file_upload.pt

@@ -15,10 +15,7 @@
              tal:attributes="style style;
                     accept accept|field.widget.accept;
                     data-filename fname;
-                    attributes|field.widget.attributes|{};"
-                    onchange="document.getElementById('preview-'+this.id).src = window.URL.createObjectURL(this.files[0]);
-                              document.getElementById('labeldelete-'+this.id).remove();
-                              document.getElementById('label-'+this.id).remove();"/>
+                    attributes|field.widget.attributes|{};"/>
     <input tal:define="uid cstruct.get('uid')"
              tal:condition="uid"
             type="hidden" name="uid" value="${uid}"/>
@@ -31,7 +28,11 @@
             if(this.files[0].size > ${maxsize}){
                 alert("File is too big!");
                 this.value = "";
+                document.getElementById('preview-'+this.id).src = '';
             }
+            document.getElementById('preview-'+this.id).src = window.URL.createObjectURL(this.files[0]);
+            document.getElementById('labeldelete-'+this.id).remove();
+            document.getElementById('label-'+this.id).remove();
         };
     </script>
 </tal:block>