cropper图片剪裁 ， .toBlob()报错

问题描述：

　　使用 cropper.js 剪裁图片时， 调用 toBlob() 方法报错

$("#image").cropper('getCroppedCanvas').toBlob(function (blob){})

　　报错信息：

　　Uncaught TypeError: $(...).cropper(...).toBlob is not a function

解决方法：

    /* 使用二进制方式处理dataUrl */
    function processData(dataUrl) {
        var binaryString = window.atob(dataUrl.split(',')[1]);
        var arrayBuffer = new ArrayBuffer(binaryString.length);
        var intArray = new Uint8Array(arrayBuffer);
        for (var i = 0, j = binaryString.length; i < j; i++) {
            intArray[i] = binaryString.charCodeAt(i);
        }

        var data = [intArray],
            blob;

        try {
            blob = new Blob(data);
        } catch (e) {
            window.BlobBuilder = window.BlobBuilder ||
                window.WebKitBlobBuilder ||
                window.MozBlobBuilder ||
                window.MSBlobBuilder;
            if (e.name === 'TypeError' && window.BlobBuilder) {
                var builder = new BlobBuilder();
                builder.append(arrayBuffer);
                blob = builder.getBlob(imgType); // imgType为上传文件类型，即 file.type
            } else {
                console.log('版本过低，不支持上传图片');
            }
        }
        return blob;
    }

　　最后调用代码：

    $('#cutBtn').click(function() {
        var data = $('#image').cropper('getCroppedCanvas', {
                width: 300, // 裁剪后的长宽
                height: 300
            }),
            blob = processData(data.toDataURL());

        var formData = new FormData();
        formData.append('uploadImg', blob);
        $.ajax({
            url: '/path/to/upload',
            method: "POST",
            data: formData,
            processData: false,
            contentType: false,
            success: function() {
                console.log('Upload success');
            },
            error: function() {
                console.log('Upload error');
            }
        });
    });

cropper.js 用法说明文档

https://github.com/fengyuanchen/cropperjs/blob/master/README.md