这个是研究MT的Array.From函数发现的问题:
//无参数对类数组对象调用Slice会将其转换成数组: kkk = [ 'prop0','prop1','prop2','prop3' ];
var testObj = {
0: 'prop0',
1: "prop1",
2: "prop2",
3: "prop3",
length: 4
};
var kkk = Array.prototype.slice.call(testObj);