参考误差函数javascript

Question

我有以下 javascript:

$(document).ready(function () {
        // convert bytes into friendly format
        function bytesToSize(bytes) {
            var sizes = ['Bytes', 'KB', 'MB'];
            if (bytes == 0) return 'n/a';
            var i = parseInt(Math.floor(Math.log(bytes) / Math.log(1024)));
            return (bytes / Math.pow(1024, i)).toFixed(1) + ' ' + sizes[i];
        };

        // check for selected crop region
        function checkForm() {
            if (parseInt($('#w').val())) return true;
            $('.error').html('Please select a crop region and then press Upload').show();
            return false;
        };

        // update info by cropping (onChange and onSelect events handler)
        function updateInfo(e) {
            $('#x1').val(e.x);
            $('#y1').val(e.y);
            $('#x2').val(e.x2);
            $('#y2').val(e.y2);
            $('#w').val(e.w);
            $('#h').val(e.h);
        };

        // clear info by cropping (onRelease event handler)
        function clearInfo() {
            $('.info #w').val('');
            $('.info #h').val('');
        };

        // Create variables (in this scope) to hold the Jcrop API and image size
        var jcrop_api, boundx, boundy;

        function fileSelectHandler() {

            // get selected file
            var oFile = $('#image_file')[0].files[0];

            // hide all errors
            $('.error').hide();

            // check for image type (jpg and png are allowed)
            var rFilter = /^(image\/jpeg|image\/png)$/i;
            if (!rFilter.test(oFile.type)) {
                $('.error').html('Please select a valid image file (jpg and png are allowed)').show();
                return;
            }

            // check for file size
            if (oFile.size > 250 * 1024) {
                $('.error').html('You have selected too big file, please select a one smaller image file').show();
                return;
            }

            // preview element
            var oImage = document.getElementById('preview');

            // prepare HTML5 FileReader
            var oReader = new FileReader();
            oReader.onload = function (e) {

                // e.target.result contains the DataURL which we can use as a source of the image
                oImage.src = e.target.result;
                oImage.onload = function () { // onload event handler

                    // display step 2
                    $('.step2').fadeIn(500);

                    // display some basic image info
                    var sResultFileSize = bytesToSize(oFile.size);
                    $('#filesize').val(sResultFileSize);
                    $('#filetype').val(oFile.type);
                    $('#filedim').val(oImage.naturalWidth + ' x ' + oImage.naturalHeight);

                    // destroy Jcrop if it is existed
                    if (typeof jcrop_api != 'undefined') {
                        jcrop_api.destroy();
                        jcrop_api = null;
                        $('#preview').width(oImage.naturalWidth);
                        $('#preview').height(oImage.naturalHeight);
                    }

                    setTimeout(function () {
                        // initialize Jcrop
                        $('#preview').Jcrop({
                            minSize: [32, 32], // min crop size
                            aspectRatio: 1, // keep aspect ratio 1:1
                            bgFade: true, // use fade effect
                            bgOpacity: .3, // fade opacity
                            onChange: updateInfo,
                            onSelect: updateInfo,
                            onRelease: clearInfo
                        }, function () {

                            // use the Jcrop API to get the real image size
                            var bounds = this.getBounds();
                            boundx = bounds[0];
                            boundy = bounds[1];

                            // Store the Jcrop API in the jcrop_api variable
                            jcrop_api = this;
                        });
                    }, 3000);

                };
            };

            // read selected file as DataURL
            oReader.readAsDataURL(oFile);
        }
    });

这是我的 HTML:

<div id="profileUploadModal" class="modal fade" role="dialog">
                        <div class="modal-dialog">

                            <!-- Modal content-->
                            <div class="modal-content">
                                <div class="modal-header">
                                    <button type="button" class="close" data-dismiss="modal">&times;</button>
                                    <h4 class="modal-title">Upload profilepicture</h4>
                                </div>
                                <div class="modal-body" style="text-align: center;">
                                    <div class="bbody">

                                        <!-- upload form -->
                                        <form id="upload_form" enctype="multipart/form-data" method="post" action="upload.php" onsubmit="return checkForm()">
                                            <!-- hidden crop params -->
                                            <input type="hidden" id="x1" name="x1" />
                                            <input type="hidden" id="y1" name="y1" />
                                            <input type="hidden" id="x2" name="x2" />
                                            <input type="hidden" id="y2" name="y2" />

                                            <h2>Step1: Please select image file</h2>
                                            <div><input type="file" name="image_file" id="image_file" onchange="fileSelectHandler()" /></div>

                                            <div class="error"></div>

                                            <div class="step2">
                                                <h2>Step2: Please select a crop region</h2>
                                                <img id="preview" />

                                                <div class="info">
                                                    <label>File size</label> <input type="text" id="filesize" name="filesize" />
                                                    <label>Type</label> <input type="text" id="filetype" name="filetype" />
                                                    <label>Image dimension</label> <input type="text" id="filedim" name="filedim" />
                                                    <label>W</label> <input type="text" id="w" name="w" />
                                                    <label>H</label> <input type="text" id="h" name="h" />
                                                </div>

                                                <input type="submit" value="Upload" />
                                            </div>
                                        </form>
                                    </div>
                                 </div>
                                </div>
                                </div>
                            </div>

当我运行这个时，我得到以下错误：

Uncaught ReferenceError: fileSelectHandler is not defined

我不明白为什么。如我所见，功能已经实现了吗？那么，为什么我会收到此引用错误？

Answer 1

您不需要任何这些功能都在 document.onReady 中。

在 document.ready 范围内声明的任何函数也必须从其中调用。否则，当 ready() 方法退出时，它们将失去该作用域。因此它不存在于您尝试从中调用它的范围内，因此您的错误。

定义如下：

    function bytesToSize(bytes) {
      var sizes = ['Bytes', 'KB', 'MB'];
      if (bytes == 0) return 'n/a';
      var i = parseInt(Math.floor(Math.log(bytes) / Math.log(1024)));
      return (bytes / Math.pow(1024, i)).toFixed(1) + ' ' + sizes[i];
    };

     // check for selected crop region
    function checkForm() {
      if (parseInt($('#w').val())) return true;
      $('.error').html('Please select a crop region and then press Upload').show();
      return false;
    };

     // update info by cropping (onChange and onSelect events handler)
    function updateInfo(e) {
      $('#x1').val(e.x);
      $('#y1').val(e.y);
      $('#x2').val(e.x2);
      $('#y2').val(e.y2);
      $('#w').val(e.w);
      $('#h').val(e.h);
    };

     // clear info by cropping (onRelease event handler)
    function clearInfo() {
      $('.info #w').val('');
      $('.info #h').val('');
    };

     // Create variables (in this scope) to hold the Jcrop API and image size
    var jcrop_api, boundx, boundy;

    function fileSelectHandler(e) {

      alert("I'm here!");

      // get selected file
      var oFile = $('#image_file')[0].files[0];

      // hide all errors
      $('.error').hide();

      // check for image type (jpg and png are allowed)
      var rFilter = /^(image\/jpeg|image\/png)$/i;
      if (!rFilter.test(oFile.type)) {
        $('.error').html('Please select a valid image file (jpg and png are allowed)').show();
        return;
      }

      // check for file size
      if (oFile.size > 250 * 1024) {
        $('.error').html('You have selected too big file, please select a one smaller image file').show();
        return;
      }

      // preview element
      var oImage = document.getElementById('preview');

      // prepare HTML5 FileReader
      var oReader = new FileReader();
      oReader.onload = function(e) {

        // e.target.result contains the DataURL which we can use as a source of the image
        oImage.src = e.target.result;
        oImage.onload = function() { // onload event handler

          // display step 2
          $('.step2').fadeIn(500);

          // display some basic image info
          var sResultFileSize = bytesToSize(oFile.size);
          $('#filesize').val(sResultFileSize);
          $('#filetype').val(oFile.type);
          $('#filedim').val(oImage.naturalWidth + ' x ' + oImage.naturalHeight);

          // destroy Jcrop if it is existed
          if (typeof jcrop_api != 'undefined') {
            jcrop_api.destroy();
            jcrop_api = null;
            $('#preview').width(oImage.naturalWidth);
            $('#preview').height(oImage.naturalHeight);
          }

          setTimeout(function() {
            // initialize Jcrop
            $('#preview').Jcrop({
              minSize: [32, 32], // min crop size
              aspectRatio: 1, // keep aspect ratio 1:1
              bgFade: true, // use fade effect
              bgOpacity: .3, // fade opacity
              onChange: updateInfo,
              onSelect: updateInfo,
              onRelease: clearInfo
            }, function() {

              // use the Jcrop API to get the real image size
              var bounds = this.getBounds();
              boundx = bounds[0];
              boundy = bounds[1];

              // Store the Jcrop API in the jcrop_api variable
              jcrop_api = this;
            });
          }, 3000);

        };
      };

      // read selected file as DataURL
      oReader.readAsDataURL(oFile);
    }

    $(document).ready(function() {
      // convert bytes into friendly format



    });

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<div id="profileUploadModal" class="modal fade" role="dialog">
  <div class="modal-dialog">

    <!-- Modal content-->
    <div class="modal-content">
      <div class="modal-header">
        <button type="button" class="close" data-dismiss="modal">&times;</button>
        <h4 class="modal-title">Upload profilepicture</h4>
      </div>
      <div class="modal-body" style="text-align: center;">
        <div class="bbody">

          <!-- upload form -->
          <form id="upload_form" enctype="multipart/form-data" method="post" action="upload.php" onsubmit="return checkForm()">
            <!-- hidden crop params -->
            <input type="hidden" id="x1" name="x1" />
            <input type="hidden" id="y1" name="y1" />
            <input type="hidden" id="x2" name="x2" />
            <input type="hidden" id="y2" name="y2" />

            <h2>Step1: Please select image file</h2>
            <div>
              <input type="file" name="image_file" id="image_file" onchange="fileSelectHandler()" />
            </div>

            <div class="error"></div>

            <div class="step2">
              <h2>Step2: Please select a crop region</h2>
              <img id="preview" />

              <div class="info">
                <label>File size</label>
                <input type="text" id="filesize" name="filesize" />
                <label>Type</label>
                <input type="text" id="filetype" name="filetype" />
                <label>Image dimension</label>
                <input type="text" id="filedim" name="filedim" />
                <label>W</label>
                <input type="text" id="w" name="w" />
                <label>H</label>
                <input type="text" id="h" name="h" />
              </div>

              <input type="submit" value="Upload" />
            </div>
          </form>
        </div>
      </div>
    </div>
  </div>
</div>

Answer 2

那是因为你的函数 fileSelectHandler() 是在另一个函数内部定义的。尝试将其移出 "$(document).ready(function () {..." block

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