After Upgrading SharePoint 2010 to SharePoint 2013 all the controls on form are disabled

Dear all,

I am facing issue after migrating sharepoint into sharepoint 2013.Site collection contains .aspx pages, if that have been customized using Microsoft SharePoint Designer or by changing some of the page properties, these pages not work properly after upgrade to SharePoint 2013.
All the Controls (like Dropdown, Calendar control, Check box and so on….) on NewForm.aspx page are disabled.
I check in developer tools, but shows empty. If I open same form in SharePoint designer 2013 it shows control properly.
Please Refer below Screen.

Would be great if someone can explain me how to resolve this issue or point to some articles on the same.

Thanks & Regards Mr. Bajirao Shinde