An iframe based implementation of an ajax like page does not refresh

This method is implemented based on an iframe and requires that the form form submit has an input tag with a file upload, so you cannot submit using ajax

First of all:

 
<form id="form0" action="${pageContext.request.contextPath}/news/baikeAdd.form" enctype="multipart/form-data" method="POST" target="hidden_frame"> 
... ... 
</form> 
<iframe name='hidden_frame' id="hidden_frame" style='display:none'></iframe> 

The value of the attribute at the scarlet letter must be the same