<input type="file" name="img-up" id="img-up" value="" />

$("#img-up").on("change",function () {
                if(this.files[0]){
                    getImgBase64Data(this.files[0], function (result) {
                        console.log(result);
                        
                    });
                }

            });
            function getImgBase64Data(file, callback) {
                var reader = new FileReader();
                reader.onload = function (e) {
                    callback(e.target.result);
                };
                reader.readAsDataURL(file); // 读取完后会调用onload方法
            }