javascript 用零填充字符串

Posted 2021-05-03

$(document).ready( function() {
    pad_key_num() ;
}) ;


// Helper Functions
function pad_key_num() {
    $("#key_num").on('change', function() {
        let key_num = $('#key_num').val();
        pad_key_num = String('000' + key_num ).slice(-3) ; // max number it can hold: 999, 1000 -> 000
        document.getElementById('key_num').value = pad_key_num;
    });
}