JScript ユーザーズ ガイド、配列としてのオブジェクト

everyday JScript

length の値を変更すると、縮小

ary = [1, 2, 3];

WScript.Echo(ary.length);

ary.length = 2;
for (x in ary) {
  WScript.Echo(ary[x]);
}

ary.length = 3;
for (x in ary) {
  WScript.Echo(ary[x]);
}


範囲外に代入すると、伸張

ary = [1, 2, 3];

WScript.Echo(ary.length);

ary[4] = 4;
WScript.Echo(ary.length);