Example code for implementing multiple file uploads in form using js

This article mainly introduces in detail JavaScript how to implement multiple file uploads of form forms. It has certain reference value. Interested friends can refer to it

Multiple file upload of form form, the specific content is as follows

The formData object can use a series of key-value pairs to simulate a complete form, and then use Ajax to send the form

Use the ff9c23ada1bcecdd1a0fb5d5a0f18437 form to initialize the FormData object to upload files

<!--文件上传-->
 <form id="uploadForm" enctype="multipart/form-data">
 <p class="row" style="margin-top: 20px;">
  <p class="form-group col-md-12" id="file">   
   <input type="hidden" name="_csrf-application"
     value="<?= $csrf ?>">
   <p class="form-group field-uploadform-excelfiles" style="margin-left: 30px;">
    <label class="control-label btn btn-primary"
      for="uploadform-excelfiles">选择文件</label>
    <input type="file" id="uploadform-excelfiles" name="UploadForm[excelFiles][]"
      multiple class="attachment-upload" accept=".xlsx">
    <input type="button" id="fileUpload" value="上传文件" class="btn btn-success" style="margin-left: 15px;">
    <p class="help-block"></p>
    <p id="fileName"></p>
   </p>

  </p>
 </p>
 <table role="presentation" class="table"><tbody id="files"></tbody></table> 
</form>

Note:

1. When using the formData object to upload the form, you must add the enctype="multipart/form-data" attribute to the form.
2. When using the formData object to upload the form, you must start filling in the value according to name. Attributes are put into this object. You cannot start using action to upload. You will use formData to upload later. This will cause errors in the uploaded data.

Get the files changed by the change event

 var fileList;
 var allFile = [];
 //FormData对象初始化
 var form = document.getElementById("upload-form");
 var formData = new FormData(form);
 $("#uploadform-excelfiles").on('change', function (e) {
  //获取表单数据并传入formData中
  var norm = $("#norm").val();
  var major = $("#major").val();
  var type = $("#type").val();
  formData.set("norm",norm);
  formData.set("major",major);
  formData.set("type",type);

  var fileError = 0;
  fileList = e.currentTarget.files;
  $.each(fileList, function (index, item) {
   var fileName = item.name;
   var fileEnd = fileName.substring(fileName.indexOf("."));
   //上传文件格式判断
   if (fileEnd == ".xlsx") {
    allFile.push(item);
    $(&#39;#files&#39;).append( &#39;<tr style="padding-top: 7px;">&#39; +
         &#39;<td>&#39;+fileName+&#39;</td>&#39; +
         &#39;<td>&#39;+(item.size / 1024).toFixed(2)+&#39;K</td>&#39; +
         &#39;<td><input type="button" class="btn btn-danger delete" value="删除"></td>&#39; +
         &#39;</tr>&#39;);
    //追加文件
    formData.append(&#39;UploadForm[excelFiles][]&#39;,item);
   } else {
    fileError++;
   }
  });
  if (fileError > 0) {
   alert("只能上传 “.xlsx” 格式的文件!");
   document.getElementById("upload-form").reset();
   return;
  }

  var fileCount = $(&#39;#files&#39;).find(&#39;tr&#39;).length;
  $(&#39;#fileName&#39;).html(&#39;共上传 &#39; + fileCount + &#39; 个文件&#39;);

 });

DeleteButtonEvent

$('#files').on('click','.delete',function (e) {
  var saveFile = [];
  var norm = $("#norm").val();
  var major = $("#major").val();
  var type = $("#type").val();
  var deleteName = e.target.parentNode.previousElementSibling.previousElementSibling.textContent;
  var deleteIndex;
  //将不删除的放入数组中
  $.each(allFile,function (index, item) {
   if(item.name == deleteName){
     deleteIndex = index;
   }else {
    saveFile.push(item);
   }
  });
  allFile.splice(deleteIndex,1);
  //表单数据重置
  formData.set("norm",norm);
  formData.set("major",major);
  formData.set("type",type);
  formData.delete('UploadForm[excelFiles][]');
  //将不删除的数组追加的formData中
  $.each(saveFile,function (index, item) {
   formData.append('UploadForm[excelFiles][]',item);
  });

  e.target.parentNode.parentNode.remove();
  var fileCount = $('#files').find('tr').length;
  $('#fileName').html('共上传 ' + fileCount + ' 个文件');

 });

File Upload Event

$("#fileUpload").on('click',function () {
  var len = formData.getAll('UploadForm[excelFiles][]').length;
  $("#overlay").show();
  if(len > 1){
    var deleteBtn = $(".delete");
    //通过ajax进行上传
    $.ajax({
     url: '/finalize/upload',
     type: 'POST',
     cache: false,
     data: formData,
     processData: false,
     contentType: false
    }).done(function(res) {
     if(res.code == 'ok'){
      //进度条设置
      var value = 0;
      var timer2 = setInterval(function () {
       value ++;
       $("#progress").css('width', value + "%");
       if (value == 120) {
        clearInterval(timer2);
        $("#overlay").hide();
        alert("文件上传成功!");
       }
      }, 50);
     //删除对应按钮
     $("#fileUpload").css("display","none");
     $.each(deleteBtn,function (index, item) {
      $(item).css("display","none");
     });
     $(&#39;#files&#39;).append(&#39;<tr><td><td><td><a type="button" class="btn btn-success pull-right" id="fileDown" href="/finalize/get-file?id=&#39; + res.data.id + &#39;" rel="external nofollow" >文件下载</a></td></tr>&#39;)
    }

   }).fail(function(res) {
    alert("文件上传失败:" + res.msg);
   });
  }else {
   alert("请选择需要上传的文件！");
  }

 });

【Related recommendations】

1. Free js online video tutorial

2. JavaScript Chinese Reference Manual

3. php.cn Dugu Jiujian (3) - JavaScript video tutorial

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