<!DOCTYPE html><html><head><title>Array map() Example</title></head><body><script> var numbers = [1,2,3,4,5,4,3,2,1]; var mapResult = numbers.map(function(item, index, array){ return item * 2; }); alert(mapResult); //[2,4,6,8,10,8,6,4,2]</script></body></html>
alert 顯示的為什么不是如后面注釋所寫(xiě)的帶括號(hào)的數(shù)組？顯示出來(lái)就是2，4，6，8，10，8，6
冉冉說(shuō)
2018-12-11 13:23:42
