谁能弄清楚为什么 FileReader 对象的这个声明返回未定义?
console.log("this is f " + f);
控制台.log(f);
var reader = new FileReader();
var ref = reader.readAsArrayBuffer(f);
console.log(ref);
console.log("the reader object is " + reader.length);//why does reader not have a length property?
这是我的 jsFiddle:http: //jsfiddle.net/trkkazulu/6bV63/
谢谢,
J·威尔斯