JavaScript数组长度错误

Question

我收到错误：无法读取属性＆＃39;长度＆＃39;

var spritearray = [];

spritearray[0] = {"name": "North", "lat":0, "lon": 10};

spritearray[1] = {"name": "south", "lat":0, "lon": 20};

for (var i= 0; i< spritearray.length; i++)
{

    var Ncardinal = spritearray[i];
    sprite =  new labelBox(Ncardinal, radius, document.body);
}