JQuery Ajax Form with File Upload not working in IE

问题

I'm using Jquery Ajax Form to upload files, which works well in Chrome and Firefox, but it doesnt work in IE. It pop ups a window telling me to save the file that I'm trying to upload.

Some example of my code, if necessary, is rite here: HTML:

<div class="addNewDocumentContent">
<form id="AddNewDocForm" action="@Url.Action("AddNewDocument", "BidForm")" enctype="multipart/form-data" method="post">
<div>
    <input name="File" type="file" style="width: 80%;" />
</div>
<div>
    <label>
        @Labels.Name</label>
    <input type="text" name="Name" style="width: 80%;" />
</div>
<div style="text-align: right;">
    <button type="button" name="Back" value="Back">
       @Buttons.GoBack
    </button>
    <button type="submit" name="Add" value="Back">
        @Buttons.Add
    </button>
</div>
</form>

JS:

//Document Ready=============================================================================
$(function () { 

    $('#AddNewDocForm').ajaxForm({
        type: 'POST',
        beforeSubmit: function () {
            return $("#AddNewDocForm").valid();
        },
        success: function (documents) {
            FillDocuments(documents);
            $('#dialogAddNewDocument').dialog('close');
        }
    });
});
//Validate====================================================================================
//Validation=====================================================================================
$(function () {
    $("#AddNewDocForm").validate({
        ignore: ":not(:visible)",
        rules: {
            File: "required",
            Name: "required"
        }
    });
});
//=========================================================================================

Action

[HttpPost]
    public JsonResult AddNewDocument(DocumentModel document)
    {
        if (ModelState.IsValid)
        {
            List<DocumentModel> documents = null;
            if (Session["Documents"] != null)
            {
                documents = (List<DocumentModel>)Session["Documents"];
                var doc = documents.OrderByDescending(x => x.Number).Take(1).FirstOrDefault();

                document.Number = doc != null ? doc.Number + 1 : 1;
                document.FileName = document.File != null ? document.File.FileName : document.FileName;
                documents.Add(document);
            }
            else
            {
                documents = new List<DocumentModel>();
                document.Number = 1;
                document.FileName = document.File != null ? document.File.FileName : document.FileName;
                documents.Add(document);
                Session["Documents"] = documents;
            }

            var displaydocs = documents.Select(x => new
            {
                Name = x.Name,
                Number = x.Number,
                File = x.File != null ? x.File.FileName : x.FileName,
                Route = x.Route != null ? x.Route : "#",
            });

            return Json(displaydocs, JsonRequestBehavior.AllowGet);
        }
        else
        {
            return null;
        }
    }

and finally model:

  public class DocumentModel
{
    public int Number { get; set; }
    [Required]
    public string Name { get; set; }
    [Required]
    public HttpPostedFileBase File { get; set; }

    public string FileName { get; set; }
    public string Route { get; set; }
}

Again, it works in every browser except IE8. Im probably not the only one, but I havent found an answer out there.

回答1:

This question has been asked many times. Please search before posting. The documentation states it clearly:

Browsers that support the XMLHttpRequest Level 2 will be able to upload files seamlessly and even get progress updates as the upload proceeds. For older browsers, a fallback technology is used which involves iframes since it is not possible to upload files using the level 1 implmenentation of the XMLHttpRequest object. This is a common fallback technique, but it has inherent limitations. The iframe element is used as the target of the form's submit operation which means that the server response is written to the iframe. This is fine if the response type is HTML or XML, but doesn't work as well if the response type is script or JSON, both of which often contain characters that need to be repesented using entity references when found in HTML markup.

To account for the challenges of script and JSON responses when using the iframe mode, the Form Plugin allows these responses to be embedded in a textarea element and it is recommended that you do so for these response types when used in conjuction with file uploads and older browsers. Please note, however, that if there is no file input in the form then the request uses normal XHR to submit the form (not an iframe). This puts the burden on your server code to know when to use a textarea and when not to.

Since you are returning JSON from your controller action you need to respect what the documentation says => wrap in a <textarea> element.

回答2:

I haven't tried with a textarea yet, but it works fine if I define the content type to return inside the action as text/html:

 return new JsonResult() { ContentType = "text/html", Data = result };

回答3:

Try to add cache:'false' inside your AJAX call... Something like:

 $.ajax({
 type:"POST", 
 url:'process.php',
 cache:'false',   //IE FIX
 data: data, 
 success: function(){ //on success do something...

 } 
 });

来源：https://stackoverflow.com/questions/11233610/jquery-ajax-form-with-file-upload-not-working-in-ie