使用FileReader时，chrome中的状态错误无效

Question

I'm simply trying to use FileReader to display image files, however when I try to use more than 1 image, I get the following "InvalidStateError: DOM Exception 11". In firefox, however, it works fine.

Here's my code

    function addImages(images)
            {
                var reader=new FileReader()

                reader.onload=function()
                {
                    $("#images").append('<img src="'+this.result+'"/><br/>')
                }

                for(var count=0;count<images.length;count++)
                {
                    reader.readAsDataURL(images[count])
                }
            }

            function uploadImagesToBrowser(e)
            {
                addImages(e.target.files)   
            }
$("#imagefiles").on("change",uploadImagesToBrowser)

Answer 1

Unfortunately doesn't work. As mentioned by janje you will need to create a new FileReader per iteration. Also remember to create a closure when binding the event handler, due to the " creating functions in a loop " problem in JavaScript.

Eric Bidelman's post is a rather good source:

function handleFileSelect(evt) {
    var files = evt.target.files; // FileList object

    // Loop through the FileList and render image files as thumbnails.
    for (var i = 0, f; f = files[i]; i++) {

      var reader = new FileReader();

      // Closure to capture the file information.
      reader.onload = (function(theFile) {
        return function(e) {
          // Render thumbnail.
        };
      })(f);

      // Read in the image file as a data URL.
      reader.readAsDataURL(f);
    }
  }

Answer 2

您必须使用readAsDataURL为每次迭代创建一个新的FileReader（以及一个用于存储它的新变量）。