将DIV更改为外部表单页面，一旦提交仅更新DIV

So I googled AJAX, JQuery, JSON, InnerHTML and a few other things. I cant find any working examples for changing a DIV to an external page which has a form. If the form passes validation the original DIV is refreshed to the new update content from the form.So I googled AJAX, JQuery, JSON, InnerHTML and