jquery 实现拖动文件上传加载进度条功能

//进度条<div class="parent-dlg" > <div class="progress-label">0%</div> <div class="son"></div></div>//要拖动到的地方<div class="main_content_center"></div>

var dz = $('#main_content_center');dz.ondragover = function(ev) { //阻止浏览器默认打开文件的操作 ev.preventDefault();}dz.ondrop = function(ev) { ev.preventDefault(); var files = ev.dataTransfer.files; var len = files.length,i = 0; while (i < len) {  var filesName=files[i].name;  var extStart=filesName.lastIndexOf(".");  var ext=filesName.substring(extStart,filesName.length).toUpperCase();  if(ext!=".JPG"&&ext!=".PNG"&&ext!=".XML"){ //判断是否是需要的问件类型  TS.errorAlert("请选择.jpg、.png、.xml类型的文件上传！");  return false;  }else{  test(files[i]);  }  i++; } $(".parent-dlg").show();}function test(a){ var formData = new FormData(); formData.append("name", a.name); formData.append("size", a.size); formData.append("data", a); $.ajax({ url:'', type:'post', data:formData, cache: false, processData: false, contentType: false, xhr: function(){ var xhr = $.ajaxSettings.xhr(); if(onprogress && xhr.upload) {  xhr.upload.addEventListener("progress" , onprogress, false);  return xhr; } }  })};function onprogress(evt){ var loaded = evt.loaded;  //已经上传大小情况  var tot = evt.total;  //附件总大小  var per = Math.floor(100*loaded/tot); //已经上传的百分比  $(".progress-label").html( per +"%" ); $(".son").css("width" , per +"%"); if(per>=100){ $(".parent-dlg").hide(); } }

.parent-dlg{position: absolute;width:400px; height:20px; border:1px solid #aaaaaa;border-radius:3px;top:30%;left:50%;z-index:9999;margin-left:-200px;display:none;}.parent-dlg .progress-label{position: absolute;left: 50%;top: 4px;font-weight: bold;text-shadow: 1px 1px 0 #fff;} .parent-dlg .son {width:0; height:100%; background-color:#cccccc; text-align:center; line-height:20px; font-size:16px; font-weight:bold;}