JavaScript - RegEx

1st letter is alphabaetic

JavaScript

var str='123456789111111';
var reg = /^\d{15,16}$/;
console.log(reg.test(str));


var multipleAccountNumbers = '1234567890091876';
				var reg1 = /^\d{15,16}$/;
        
        console.log(multipleAccountNumbers.match(reg1));