jQuery的文件上传进度栏

我正在尝试在我的项目中实现AJAX文件上传功能。我为此使用jQuery；我的代码使用AJAX提交数据。我也想实现一个文件上传进度条。我怎样才能做到这一点？有什么方法可以计算已经上传的数量，以便我可以计算上传的百分比并创建进度条？

注意：此问题与jQuery form插件有关。如果您正在寻找纯jQuery解决方案，请从此处开始。没有针对所有浏览器的整体jQuery解决方案。因此，您必须使用插件。我使用的是dropzone.js，对于较旧的浏览器来说，它有一个简单的备用。您更喜欢哪种插件取决于您的需求。那里有很多比较好的帖子。

从示例：

jQuery的：

$(function() {

    var bar = $('.bar');
    var percent = $('.percent');
    var status = $('#status');

    $('form').ajaxForm({
        beforeSend: function() {
            status.empty();
            var percentVal = '0%';
            bar.width(percentVal);
            percent.html(percentVal);
        },
        uploadProgress: function(event, position, total, percentComplete) {
            var percentVal = percentComplete + '%';
            bar.width(percentVal);
            percent.html(percentVal);
        },
        complete: function(xhr) {
            status.html(xhr.responseText);
        }
    });
}); 

的HTML：

<form action="file-echo2.php" method="post" enctype="multipart/form-data">
    <input type="file" name="myfile"><br>
    <input type="submit" value="Upload File to Server">
</form>

<div class="progress">
    <div class="bar"></div >
    <div class="percent">0%</div >
</div>

<div id="status"></div>

您必须使用CSS设置进度条的样式...

我只用jQuery完成了此操作：

$.ajax({
  xhr: function() {
    var xhr = new window.XMLHttpRequest();

    xhr.upload.addEventListener("progress", function(evt) {
      if (evt.lengthComputable) {
        var percentComplete = evt.loaded / evt.total;
        percentComplete = parseInt(percentComplete * 100);
        console.log(percentComplete);

        if (percentComplete === 100) {

        }

      }
    }, false);

    return xhr;
  },
  url: posturlfile,
  type: "POST",
  data: JSON.stringify(fileuploaddata),
  contentType: "application/json",
  dataType: "json",
  success: function(result) {
    console.log(result);
  }
});

我在项目中使用了以下内容。您也可以尝试。

ajax = new XMLHttpRequest();
ajax.onreadystatechange = function () {

    if (ajax.status) {

        if (ajax.status == 200 && (ajax.readyState == 4)){
            //To do tasks if any, when upload is completed
        }
    }
}
ajax.upload.addEventListener("progress", function (event) {

    var percent = (event.loaded / event.total) * 100;
    //**percent** variable can be used for modifying the length of your progress bar.
    console.log(percent);

});

ajax.open("POST", 'your file upload link', true);
ajax.send(formData);
//ajax.send is for uploading form data.

检查一下：http : //hayageek.com/docs/jquery-upload-file.php 我在网上偶然发现了它。

如果您在项目上使用jquery，并且不想从头开始实现上传机制，则可以使用https://github.com/blueimp/jQuery-File-Upload。

他们有一个非常不错的api，可以选择多个文件，拖放支持，进度条，验证和预览图像，跨域支持，分块和可恢复的文件上传。并且它们具有用于多种服务器语言（节点，php，python和go）的示例脚本。

演示网址：https : //blueimp.github.io/jQuery-File-Upload/。

这是一个看起来更完整的jquery 1.11.x $ .ajax（）用法：

<script type="text/javascript">
    function uploadProgressHandler(event) {
        $("#loaded_n_total").html("Uploaded " + event.loaded + " bytes of " + event.total);
        var percent = (event.loaded / event.total) * 100;
        var progress = Math.round(percent);
        $("#uploadProgressBar").html(progress + " percent na ang progress");
        $("#uploadProgressBar").css("width", progress + "%");
        $("#status").html(progress + "% uploaded... please wait");
    }

    function loadHandler(event) {
        $("#status").html(event.target.responseText);
        $("#uploadProgressBar").css("width", "0%");
    }

    function errorHandler(event) {
        $("#status").html("Upload Failed");
    }

    function abortHandler(event) {
        $("#status").html("Upload Aborted");
    }

    $("#uploadFile").click(function (event) {
        event.preventDefault();
        var file = $("#fileUpload")[0].files[0];
        var formData = new FormData();
        formData.append("file1", file);

        $.ajax({
            url: 'http://testarea.local/UploadWithProgressBar1/file_upload_parser.php',
            method: 'POST',
            type: 'POST',
            data: formData,
            contentType: false,
            processData: false,
            xhr: function () {
                var xhr = new window.XMLHttpRequest();
                xhr.upload.addEventListener("progress",
                    uploadProgressHandler,
                    false
                );
                xhr.addEventListener("load", loadHandler, false);
                xhr.addEventListener("error", errorHandler, false);
                xhr.addEventListener("abort", abortHandler, false);

                return xhr;
            }
        });
    });
</script>

这解决了我的问题

$.ajax({
  xhr: function() {
    var xhr = new window.XMLHttpRequest();

    xhr.upload.addEventListener("progress", function(evt) {
      if (evt.lengthComputable) {
        var percentComplete = evt.loaded / evt.total;
        percentComplete = parseInt(percentComplete * 100);
var $link = $('.'+ids);
          var $img = $link.find('i'); 
          $link.html('Uploading..('+percentComplete+'%)');
          $link.append($img);
      }
    }, false);

    return xhr;
  },
  url: posturlfile,
  type: "POST",
  data: JSON.stringify(fileuploaddata),
  contentType: "application/json",
  dataType: "json",
  success: function(result) {
    console.log(result);
  }
});

Kathir的答案很棒，因为他只用jQuery就解决了这个问题。我只是想对他的答案做一些补充，以使用漂亮的HTML进度条来处理他的代码：

$.ajax({
xhr: function() {
var xhr = new window.XMLHttpRequest();

xhr.upload.addEventListener("progress", function(evt) {
  if (evt.lengthComputable) {
    var percentComplete = evt.loaded / evt.total;
    percentComplete = parseInt(percentComplete * 100);

    $('.progress-bar').width(percentComplete+'%');
    $('.progress-bar').html(percentComplete+'%');

  }
}, false);

return xhr;
},
url: posturlfile,
type: "POST",
data: JSON.stringify(fileuploaddata),
contentType: "application/json",
dataType: "json",
success: function(result) {
console.log(result);
}
});

这是进度条的HTML代码，我将Bootstrap 3用于进度条元素：

<div class="progress" style="display:none;">
<div class="progress-bar progress-bar-success progress-bar-striped 
active" role="progressbar"
aria-valuemin="0" aria-valuemax="100" style="width:0%">
0%
</div>
</div>

JavaScript：

<script>
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</script>
    <script type="text/javascript">
        $(document).ready(function () {
            $('#myform').on('change', '.wpcf7-file', function (e) {
                e.preventDefault();
                var myParent = $(this).parent();
                var filname= $('input[type=file]').val()

                if (filname) { 
                $(this).parent().find('#progress-div').show();          
                $('#myform').ajaxSubmit({
                    // target: '#progress-div123',/**********only for response************/
                    beforeSubmit: function () {
                        myParent.find('#progress-bar').width('0%');
                    },
                    uploadProgress: function (event, position, total, percentComplete) {
                        myParent.find('#progress-bar').width(percentComplete + '%');
                        myParent.find('#progress-bar').html('<div id="progress-status">' + percentComplete + ' %</div>')
                    },
                    success: function showResponse(responseText, statusText, xhr, $form) {

                        //myParent.find('#progress-div').hide(10000);
                    },
                    resetForm: false
                });

                }
                return false;
            });


           /***********Error msg if file not valid***************/
                $('input[type=file]').change(function () {
                var val = $(this).val().toLowerCase();
                var regex = new RegExp("(.*?)\.(pdf|txt|jpg|png|doc|docx|xlx|xls|xlsx|jpg|ppt|pptx|tif|tiff|\n\
                bmp|pcd|gif|bmp|zip|rar|odt|avi|ogg|m4a|mov|mp3|mp4|mpg|wav|wmv|stp|sldprt|sldasm|iges|igs|stl|x_t|step\n\
                |stp|prt|asm|idw|iam|ipt|dxf|dwg|pdf|slddrw|dwf)$");
                if (!(regex.test(val))) {
                    $(this).val('');
                    alert('Please select correct file format');
                }
                });
            /*********End*****************/

        });
</script>

样式：

<style>
    body{width:610px;}
    #uploadForm {border-top:#F0F0F0 2px solid;background:#FAF8F8;padding:10px;}
    #uploadForm label {margin:2px; font-size:1em; font-weight:bold;}
    .demoInputBox{padding:5px; border:#F0F0F0 1px solid; border-radius:4px; background-color:#FFF;}
    #progress-bar {background-color: #12CC1A;height:20px;color: #FFFFFF;width:0%;-webkit-transition: width .3s;-moz-transition: width .3s;transition: width .3s;}
    .btnSubmit{background-color:#09f;border:0;padding:10px 40px;color:#FFF;border:#F0F0F0 1px solid; border-radius:4px;}
    #progress-div
    {
        border: 1px solid #0fa015;
        border-radius: 4px;
        margin: -35px 2px 7px 295px;
        padding: 5px 0;
        text-align: center;
        width: 277px;
    }

    #targetLayer{width:100%;text-align:center;}
</style>