如何从HTML5 FileReader中的"输入类型"清除以前的文件

Question

我有一个文件输入:

<img id="uploadPreview">
   <div id="changeImage">Change</div>
<div id="customImage">
   <input type="file" id="myfile" multiple style="display:none" onchange="PreviewImage();" />
   <div class='upload blank' id="add-image"></div>
</div>

功能如下:

var oFReader = new FileReader();
oFReader.readAsDataURL(document.getElementById("myfile").files[0]);

oFReader.onload = function (oFREvent) {
    document.getElementById("uploadPreview").src = oFREvent.target.result;
};

function PreviewImage() {
        var oFReader = new FileReader();
        oFReader.readAsDataURL(document.getElementById("myfile").files[0]);
        $("#uploadPreview").removeClass('hide'); //for manipulating something in the dom
        $('#changeImage').removeClass('hide'); //for manipulating something in the dom
        $("#customImage").addClass('hide'); //these are for manipulating something in the dom

        oFReader.onload = function (oFREvent) {
            document.getElementById("uploadPreview").src = oFREvent.target.result;
        };
    };

一切都很完美.现在我有一个更改按钮.我希望如果有人点击它,那么之前上传的文件细节就会消失.功能如下所示:

$('#changeImage').click(function(){
  $('#uploadPreview').addClass('hide');
  $('#customImage').removeClass('hide');
  //here I want to remove/clear the details about the already previous uploaded file in the 'file-input'. So the same image can be shown if someone clicks it for once again. 

});

你可以帮忙吗？

Answer 1

如果您希望将数据保存在其他表单字段中,则可以使用

HTML

    <input type='file' id='yourid' />

jQuery的

    $('#yourid').val('');

这将从输入标签中清除您上传的文件

Answer 2

如果将文件输入放在<form>标记内,则可以使用内置.reset()方法.

HTML:

<img id="uploadPreview">
   <div id="changeImage">Change</div>
<div id="customImage">
   <form id="fileform">
      <input type="file" id="myfile" multiple style="display:none" onchange="PreviewImage();" />
   </form>
   <div class='upload blank' id="add-image"></div>
</div>

JS:

$('#changeImage').click(function(){
   $('#uploadPreview').addClass('hide');
   $('#customImage').removeClass('hide');
   // Reset the form
   $("#fileform")[0].reset();
});

没有jQuery的JS:

var resetButton = document.getElementById('resetButton');
var fileInput = document.getElementById('fileInput');
var form = document.getElementById('form');

resetButton.addEventListener('click', function () {
    // resetting the file input only
    fileInput.value = null;

    // alternatively: resetting the entire form (works in older browsers too)
    form.reset();
});