Question

I’m trying to use the iframe hack to simulate an Ajax query where I can send a file to the server. It is working perfectly with IE (7, 8, 9). My ASP.NET server receive the file and can read its content.

But when I try to use the same form with Chrome or Firefox, the ASP.NET Server is still receiving a file (count = 1), but it is empty (contentLength = 0). With Fiddler, I can see the content of the file when I’m using IE, and I can see the empty file sent from Chrome and Firefox.

Here is my simplified HTML

<form id="importForm" method="post" enctype="multipart/form-data">
  <input type="file" id="importFileUpload" name="importFileUpload" class="importFileUpload" />
  <input id="importNewListButton" type="button" class="importexportButton" value="send it" />
</form>
<iframe id="importUploadFileIframe" name="importUploadFileIframe" src="" style="width:0;height:0;border:0px solid #fff;display:none;"></iframe>

Here is my simplified jQuery

$("form#importForm").attr("action", "myScript.aspx");
$("form#importForm").attr("target", "importUploadFileIframe");
$("form#importForm").submit();

And here is my simplified C#

HttpPostedFile file = Request.Files[0];
Helper.log("file = " + file.FileName);
Helper.log("file = " + file.ContentType);
Helper.log("file = " + file.ContentLength);

Answer 1

I just found out that an event I was triggering on my form (before submitting it) with the following code was the problem :

$("form#importForm").ready(function(){ ... });

If I remove this event, Chrome and Firefox (and still IE) will receive my file. Hope this could help somebody.