请帮助解决运行以下代码时控制台中出现的未定义错误
另请参阅此 JSbin http://jsbin.com/ONOwujA/1/edit
data = [
{key:"home",value:"hk1"},
{key:"home",value:"hk2"},
{key:"home",value:"hk3"},
{key:"home",value:"hk4"},
{key:"product",value:"pk1"},
{key:"product",value:"pk2"},
{key:"product",value:"pk3"},
{key:"product",value:"pk4"},
{key:"service",value:"sk1"},
{key:"service",value:"sk2"},
{key:"service",value:"sk3"},
{key:"service",value:"sk4"}
];
myFilteredKey=[];
for(i=0;i<=data.length;i++){
if(myFilteredKey.indexOf(data[i].key)!=-1){
myFilteredKey.push(data[i].key);
console.log(data[i].key);
}
}