JS问题！！！* ** *** **** 排列！求教！！

Question

 var arr = ["*","**","***","****"];arr.length=8;//创建数组 alert("数组arr 的length 长度是："+ arr.length );为什么要写成 var arr = ['*','##',"***","&&","****","##*"]; arr[7] = "**";  //显示数组长度  alert("数组arr 的length 长度是："+ arr.length );    

Answer 1

array的长度以arr最后一个元素为准！