function addFile() {            var file = this.files[0];            if (!/image\/\w+/.test(file.type)) {                alert('上传的不是图片');                this.value = "";                return false;            }            var obj = this;            var objUrl = getObjectURL(file);            var image = new Image();            image.src = objUrl;            image.onload = function () {                if (this.width != 338 || this.height != 338) {                    alert("文件尺寸不正确!");                    obj.value = "";                    return false;                }                //alert("图片的宽度为" + this.width + ",长度为" + this.height);            };            return true;        }