Html5 input[type='file'] 把图片转换成base64

  function _addImgFileListener(obj, fun)
    {
        $(obj).change(function ()
        {
            try
            {
                var file = this.files[0];
                var reader = new FileReader();
                reader.onload = function ()
                {
                    var img = new Image();
                    img.src = reader.result;
                    img.onload = function ()
                    {
                        var w = img.width, h = img.height;
                        var canvas = document.createElement('canvas');
                        var ctx = canvas.getContext('2d');
                        $(canvas).attr({
                            width: w,
                            height: h
                        });
                        ctx.drawImage(img, 0, 0, w, h);
                        var base64 = canvas.toDataURL('image/jpeg', 0.5);
                        var result = {
                            url: window.URL.createObjectURL(file),
                            base64: base64,
                            clearBase64: base64.substr(base64.indexOf(',') + 1),
                            suffix: base64.substring(base64.indexOf('/') + 1, base64.indexOf(';')),
                        };
                        fun(result);
                    }
                }
                reader.readAsDataURL(this.files[0]);
            } catch (e)
            {
                _showMsg(e);
            }
        });

    }

$(document).ready(function(){

_addImgFileListener("#uploadimg",function(data)

{

    //你的业务

}

);

})

<input type="file" class="uploading" name="file" id="uploadimg" accept="image/jpg,image/jpeg,image/gif,image/png">