我可以使用以下jQuery代码使用ajax请求的POST方法执行文件上载吗?

$.ajax({
    type: "POST",
    timeout: 50000,
    url: url,
    data: dataString,
    success: function (data) {
        alert('success');
        return false;
    }
});

如果可能,我需要填写数据部分吗?这是正确的方式吗?我只将文件POST到服务器端。

我一直在搜索,但我发现的是一个插件,而在我的计划中,我不想使用它。至少目前是这样。


当前回答

我已经很晚了,但我正在寻找一个基于ajax的图像上传解决方案,我正在寻找的答案在这篇文章中有点分散。我确定的解决方案涉及FormData对象。我组装了一个基本形式的代码。您可以看到它演示了如何使用fd.append()向表单添加自定义字段,以及如何在完成ajax请求时处理响应数据。

上传html:

<!DOCTYPE html>
<html>
<head>
    <title>Image Upload Form</title>
    <script src="//code.jquery.com/jquery-1.9.1.js"></script>
    <script type="text/javascript">
        function submitForm() {
            console.log("submit event");
            var fd = new FormData(document.getElementById("fileinfo"));
            fd.append("label", "WEBUPLOAD");
            $.ajax({
              url: "upload.php",
              type: "POST",
              data: fd,
              processData: false,  // tell jQuery not to process the data
              contentType: false   // tell jQuery not to set contentType
            }).done(function( data ) {
                console.log("PHP Output:");
                console.log( data );
            });
            return false;
        }
    </script>
</head>

<body>
    <form method="post" id="fileinfo" name="fileinfo" onsubmit="return submitForm();">
        <label>Select a file:</label><br>
        <input type="file" name="file" required />
        <input type="submit" value="Upload" />
    </form>
    <div id="output"></div>
</body>
</html>

如果您使用php,这里有一种处理上传的方法,包括使用上面html中演示的两个自定义字段。

上传.php

<?php
if ($_POST["label"]) {
    $label = $_POST["label"];
}
$allowedExts = array("gif", "jpeg", "jpg", "png");
$temp = explode(".", $_FILES["file"]["name"]);
$extension = end($temp);
if ((($_FILES["file"]["type"] == "image/gif")
|| ($_FILES["file"]["type"] == "image/jpeg")
|| ($_FILES["file"]["type"] == "image/jpg")
|| ($_FILES["file"]["type"] == "image/pjpeg")
|| ($_FILES["file"]["type"] == "image/x-png")
|| ($_FILES["file"]["type"] == "image/png"))
&& ($_FILES["file"]["size"] < 200000)
&& in_array($extension, $allowedExts)) {
    if ($_FILES["file"]["error"] > 0) {
        echo "Return Code: " . $_FILES["file"]["error"] . "<br>";
    } else {
        $filename = $label.$_FILES["file"]["name"];
        echo "Upload: " . $_FILES["file"]["name"] . "<br>";
        echo "Type: " . $_FILES["file"]["type"] . "<br>";
        echo "Size: " . ($_FILES["file"]["size"] / 1024) . " kB<br>";
        echo "Temp file: " . $_FILES["file"]["tmp_name"] . "<br>";

        if (file_exists("uploads/" . $filename)) {
            echo $filename . " already exists. ";
        } else {
            move_uploaded_file($_FILES["file"]["tmp_name"],
            "uploads/" . $filename);
            echo "Stored in: " . "uploads/" . $filename;
        }
    }
} else {
    echo "Invalid file";
}
?>

其他回答

通过ajax上传文件不再需要Iframes。我最近自己做过。查看以下页面:

使用AJAX和jQuery上传HTML5文件

http://dev.w3.org/2006/webapi/FileAPI/#FileReader-界面

更新了答案并进行了清理。使用getSize函数检查大小或使用getType函数检查类型。添加了progressbar html和css代码。

var Upload = function (file) {
    this.file = file;
};

Upload.prototype.getType = function() {
    return this.file.type;
};
Upload.prototype.getSize = function() {
    return this.file.size;
};
Upload.prototype.getName = function() {
    return this.file.name;
};
Upload.prototype.doUpload = function () {
    var that = this;
    var formData = new FormData();

    // add assoc key values, this will be posts values
    formData.append("file", this.file, this.getName());
    formData.append("upload_file", true);

    $.ajax({
        type: "POST",
        url: "script",
        xhr: function () {
            var myXhr = $.ajaxSettings.xhr();
            if (myXhr.upload) {
                myXhr.upload.addEventListener('progress', that.progressHandling, false);
            }
            return myXhr;
        },
        success: function (data) {
            // your callback here
        },
        error: function (error) {
            // handle error
        },
        async: true,
        data: formData,
        cache: false,
        contentType: false,
        processData: false,
        timeout: 60000
    });
};

Upload.prototype.progressHandling = function (event) {
    var percent = 0;
    var position = event.loaded || event.position;
    var total = event.total;
    var progress_bar_id = "#progress-wrp";
    if (event.lengthComputable) {
        percent = Math.ceil(position / total * 100);
    }
    // update progressbars classes so it fits your code
    $(progress_bar_id + " .progress-bar").css("width", +percent + "%");
    $(progress_bar_id + " .status").text(percent + "%");
};

如何使用Upload类

//Change id to your id
$("#ingredient_file").on("change", function (e) {
    var file = $(this)[0].files[0];
    var upload = new Upload(file);

    // maby check size or type here with upload.getSize() and upload.getType()

    // execute upload
    upload.doUpload();
});

Progressbar html代码

<div id="progress-wrp">
    <div class="progress-bar"></div>
    <div class="status">0%</div>
</div>

Progressbar css代码

#progress-wrp {
  border: 1px solid #0099CC;
  padding: 1px;
  position: relative;
  height: 30px;
  border-radius: 3px;
  margin: 10px;
  text-align: left;
  background: #fff;
  box-shadow: inset 1px 3px 6px rgba(0, 0, 0, 0.12);
}

#progress-wrp .progress-bar {
  height: 100%;
  border-radius: 3px;
  background-color: #f39ac7;
  width: 0;
  box-shadow: inset 1px 1px 10px rgba(0, 0, 0, 0.11);
}

#progress-wrp .status {
  top: 3px;
  left: 50%;
  position: absolute;
  display: inline-block;
  color: #000000;
}

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。

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;
}

如果你想这样做:

$.upload( form.action, new FormData( myForm))
.progress( function( progressEvent, upload) {
    if( progressEvent.lengthComputable) {
        var percent = Math.round( progressEvent.loaded * 100 / progressEvent.total) + '%';
        if( upload) {
            console.log( percent + ' uploaded');
        } else {
            console.log( percent + ' downloaded');
        }
    }
})
.done( function() {
    console.log( 'Finished upload');                    
});

https://github.com/lgersman/jquery.orangevolt-ampere/blob/master/src/jquery.upload.js

可能是您的解决方案。

如许多答案所示,使用FormData是一种方法。这里有一些代码非常适合这个目的。我也同意嵌套ajax块以完成复杂环境的意见。通过包括e.PreventDefault();根据我的经验,使代码更易于跨浏览器兼容。

    $('#UploadB1').click(function(e){        
    e.preventDefault();

    if (!fileupload.valid()) {
        return false;            
    }

    var myformData = new FormData();        
    myformData.append('file', $('#uploadFile')[0].files[0]);

    $("#UpdateMessage5").html("Uploading file ....");
    $("#UpdateMessage5").css("background","url(../include/images/loaderIcon.gif) no-repeat right");

    myformData.append('mode', 'fileUpload');
    myformData.append('myid', $('#myid').val());
    myformData.append('type', $('#fileType').val());
    //formData.append('myfile', file, file.name); 

    $.ajax({
        url: 'include/fetch.php',
        method: 'post',
        processData: false,
        contentType: false,
        cache: false,
        data: myformData,
        enctype: 'multipart/form-data',
        success: function(response){
            $("#UpdateMessage5").html(response); //.delay(2000).hide(1); 
            $("#UpdateMessage5").css("background","");

            console.log("file successfully submitted");
        },error: function(){
            console.log("not okay");
        }
    });
});