1.488Mpps是如何计算出来的

//定义一对象
var point = {x:20, y:30};
alert("x" in point);//true
alert("toString" in point);//true 继承属性
alert("z" in point);//false
for (var i in point)
{
alert(i + ":" + point[i]);
}

//定义一数组
var arr = [1212,"ds"];
for (var x in arr)
{
alert(x + ":" + arr[x])
}