<input class="form-control cu-b-border" type="file" id="formFile">
<img id="myImg" src="#">

在js中

<script>
    var formData = new FormData();
    formData.append('file', $('#formFile')[0].files[0]);
    $.ajax({
        type: "POST",
        url: '/GetData/UploadImage',
        data: formData,
        processData: false, // tell jQuery not to process the data
        contentType: false, // tell jQuery not to set contentType
        success: function (data) {
            console.log(data);
            $('#myImg').attr('src', data);
        },
        error: function (xhr, ajaxOptions, thrownError) {
        }
    })
</script>

在控制器中

public ActionResult UploadImage(HttpPostedFileBase file)
        {
            string filePath = "";
            if (file != null)
            {
                string path = "/uploads/Temp/";
                if (!Directory.Exists(Server.MapPath("~" + path)))
                {
                    Directory.CreateDirectory(Server.MapPath("~" + path));
                }
                filePath = FileUpload.SaveUploadedFile(file, path);
            }
            
            return Json(filePath, JsonRequestBehavior.AllowGet);
        }

无法通过AJAX上载文件。您可以上传文件，而无需使用IFrame刷新页面。您可以在此处查看更多详细信息。

更新

XHR2支持通过AJAX上传文件。例如，通过FormData对象，但遗憾的是，它不受所有/旧浏览器的支持。

FormData支持从以下桌面浏览器版本开始。

即10+Firefox 4.0+铬7+Safari 5+歌剧12+

有关详细信息，请参阅MDN链接。

$("#submit_car").click(function() {
  var formData = new FormData($('#car_cost_form')[0]);
  $.ajax({
     url: 'car_costs.php',
     data: formData,
     contentType: false,
     processData: false,
     cache: false,
     type: 'POST',
     success: function(data) {
       // ...
     },
  });
});

编辑：注释内容类型和过程数据您可以简单地使用它通过Ajax上传文件。。。。。。提交输入不能在表单元素之外：）

在通过ajax从预览中删除不需要的文件后，我实现了一个即时预览和上传的多文件选择。

详细文档可在以下位置找到：http://anasthecoder.blogspot.ae/2014/12/multi-file-select-preview-without.html

演示：http://jsfiddle.net/anas/6v8Kz/7/embedded/result/

jsFiddle：http://jsfiddle.net/anas/6v8Kz/7/

Java脚本：

    $(document).ready(function(){
    $('form').submit(function(ev){
        $('.overlay').show();
        $(window).scrollTop(0);
        return upload_images_selected(ev, ev.target);
    })
})
function add_new_file_uploader(addBtn) {
    var currentRow = $(addBtn).parent().parent();
    var newRow = $(currentRow).clone();
    $(newRow).find('.previewImage, .imagePreviewTable').hide();
    $(newRow).find('.removeButton').show();
    $(newRow).find('table.imagePreviewTable').find('tr').remove();
    $(newRow).find('input.multipleImageFileInput').val('');
    $(addBtn).parent().parent().parent().append(newRow);
}

function remove_file_uploader(removeBtn) {
    $(removeBtn).parent().parent().remove();
}

function show_image_preview(file_selector) {
    //files selected using current file selector
    var files = file_selector.files;
    //Container of image previews
    var imageContainer = $(file_selector).next('table.imagePreviewTable');
    //Number of images selected
    var number_of_images = files.length;
    //Build image preview row
    var imagePreviewRow = $('<tr class="imagePreviewRow_0"><td valign=top style="width: 510px;"></td>' +
        '<td valign=top><input type="button" value="X" title="Remove Image" class="removeImageButton" imageIndex="0" onclick="remove_selected_image(this)" /></td>' +
        '</tr> ');
    //Add image preview row
    $(imageContainer).html(imagePreviewRow);
    if (number_of_images > 1) {
        for (var i =1; i<number_of_images; i++) {
            /**
             *Generate class name of the respective image container appending index of selected images, 
             *sothat we can match images selected and the one which is previewed
             */
            var newImagePreviewRow = $(imagePreviewRow).clone().removeClass('imagePreviewRow_0').addClass('imagePreviewRow_'+i);
            $(newImagePreviewRow).find('input[type="button"]').attr('imageIndex', i);
            $(imageContainer).append(newImagePreviewRow);
        }
    }
    for (var i = 0; i < files.length; i++) {
        var file = files[i];
        /**
         * Allow only images
         */
        var imageType = /image.*/;
        if (!file.type.match(imageType)) {
          continue;
        }

        /**
         * Create an image dom object dynamically
         */
        var img = document.createElement("img");

        /**
         * Get preview area of the image
         */
        var preview = $(imageContainer).find('tr.imagePreviewRow_'+i).find('td:first');

        /**
         * Append preview of selected image to the corresponding container
         */
        preview.append(img); 

        /**
         * Set style of appended preview(Can be done via css also)
         */
        preview.find('img').addClass('previewImage').css({'max-width': '500px', 'max-height': '500px'});

        /**
         * Initialize file reader
         */
        var reader = new FileReader();
        /**
         * Onload event of file reader assign target image to the preview
         */
        reader.onload = (function(aImg) { return function(e) { aImg.src = e.target.result; }; })(img);
        /**
         * Initiate read
         */
        reader.readAsDataURL(file);
    }
    /**
     * Show preview
     */
    $(imageContainer).show();
}

function remove_selected_image(close_button)
{
    /**
     * Remove this image from preview
     */
    var imageIndex = $(close_button).attr('imageindex');
    $(close_button).parents('.imagePreviewRow_' + imageIndex).remove();
}

function upload_images_selected(event, formObj)
{
    event.preventDefault();
    //Get number of images
    var imageCount = $('.previewImage').length;
    //Get all multi select inputs
    var fileInputs = document.querySelectorAll('.multipleImageFileInput');
    //Url where the image is to be uploaded
    var url= "/upload-directory/";
    //Get number of inputs
    var number_of_inputs = $(fileInputs).length; 
    var inputCount = 0;

    //Iterate through each file selector input
    $(fileInputs).each(function(index, input){

        fileList = input.files;
        // Create a new FormData object.
        var formData = new FormData();
        //Extra parameters can be added to the form data object
        formData.append('bulk_upload', '1');
        formData.append('username', $('input[name="username"]').val());
        //Iterate throug each images selected by each file selector and find if the image is present in the preview
        for (var i = 0; i < fileList.length; i++) {
            if ($(input).next('.imagePreviewTable').find('.imagePreviewRow_'+i).length != 0) {
                var file = fileList[i];
                // Check the file type.
                if (!file.type.match('image.*')) {
                    continue;
                }
                // Add the file to the request.
                formData.append('image_uploader_multiple[' +(inputCount++)+ ']', file, file.name);
            }
        }
        // Set up the request.
        var xhr = new XMLHttpRequest();
        xhr.open('POST', url, true);
        xhr.onload = function () {
            if (xhr.status === 200) {
                var jsonResponse = JSON.parse(xhr.responseText);
                if (jsonResponse.status == 1) {
                    $(jsonResponse.file_info).each(function(){
                        //Iterate through response and find data corresponding to each file uploaded
                        var uploaded_file_name = this.original;
                        var saved_file_name = this.target;
                        var file_name_input = '<input type="hidden" class="image_name" name="image_names[]" value="' +saved_file_name+ '" />';
                        file_info_container.append(file_name_input);

                        imageCount--;
                    })
                    //Decrement count of inputs to find all images selected by all multi select are uploaded
                    number_of_inputs--;
                    if(number_of_inputs == 0) {
                        //All images selected by each file selector is uploaded
                        //Do necessary acteion post upload
                        $('.overlay').hide();
                    }
                } else {
                    if (typeof jsonResponse.error_field_name != 'undefined') {
                        //Do appropriate error action
                    } else {
                        alert(jsonResponse.message);
                    }
                    $('.overlay').hide();
                    event.preventDefault();
                    return false;
                }
            } else {
                /*alert('Something went wrong!');*/
                $('.overlay').hide();
                event.preventDefault();
            }
        };
        xhr.send(formData);
    })

    return false;
}

使用XMLHttpRequest（）确实可以进行AJAX上载。无需iframes。可以显示上载进度。

有关详细信息，请参阅：答案https://stackoverflow.com/a/4943774/873282对jQuery Upload Progress和AJAX文件上传提出质疑。

$（“#form id”）.submit（函数（e）{e.预防违约（）；});$（“#form id”）.submit（函数（e）{var formObj=$（此）；var formURL=formObj.attr（“操作”）；var formData=新的formData（this）；$.ajax美元({url:formURL，类型：'POST'，data:formData，processData:false，contentType：false，异步：true，缓存：false，enctype:“multipart/form data”，dataType:“json”，成功：函数（数据）{if（data.success）{警报（data.success）} if（data.error）{警报（data.error）} }});});<script src=“https://cdnjs.cloudflare.com/ajax/libs/jquery/1.7.1/jquery.min.js“></script><form class=“form horizontal”id=“form id”action=“masterFileController”enctype=“multipart/form data”><button class=“btn success btn”type=“submit”id=“btn save”>提交</button></form>

servlet响应为“out.print（“您的响应”）；”