property 為 enumerable 者indices
var myArr = ['a','b','c'];
myArr['food'] = '燃麵'
console.log(myArr) // ["a", "b", "c"]
for (var i=0; i<myArr.length;i++) {
console.log( myArr[i] );
} // 'a','b','c'
for (item in myArr) {
console.log( item );
} // "0","1","2","food"
只看一點點，以上理解有所出入，都在麻煩協助提點了，感謝 ԅ(≖‿≖ԅ)
iThome鐵人賽
看影片追技術