javascript - 如何区分数字串和字符串？

Question

var snumber1 = "123456789";
var scharacter2 = "abcdefgh";

有两个字符串。我如何确保 snumber1 仅包含数字？ 什么正则表达式？？

Answer 1

var snumber1 = "123456789";
//built-in function
alert ( !isNaN ( snumber1 ) );
//regexp
alert ( /^[0-9]+$/.test ( snumber1 ) );
//another regexp
alert ( /^\d+$/.test ( snumber1 ) );
//convert to Number object
alert ( parseFloat ( snumber1 ) === Number ( snumber1 ) );