「JavaScript」padStartメソッドで頭0をつけるサンプル
書式
文字列.padStart(文字列の長さ[,埋める文字]);
使用例
<script>
const cftA = "8";
console.log(cftA.padStart(3, "0"));
console.log(cftA.padStart(4, "0"));
const cftB = "60";
console.log(cftB.padStart(3, "0"));
console.log(cftB.padStart(4, "0"));
</script>
<script>
const cftA = "8";
console.log(cftA.padStart(3, "0"));
console.log(cftA.padStart(4, "0"));
const cftB = "60";
console.log(cftB.padStart(3, "0"));
console.log(cftB.padStart(4, "0"));
</script>
<script>
const cftA = "8";
console.log(cftA.padStart(3, "0"));
console.log(cftA.padStart(4, "0"));
const cftB = "60";
console.log(cftB.padStart(3, "0"));
console.log(cftB.padStart(4, "0"));
</script>
実行結果
008
0008
060
0060