[JS] 判斷字串是否為integer

下面例子會跳出alert視窗, 顯示回傳值為false(1235.6不是整數)

<script language="javascript">
Object.prototype.isInteger = function () {
  return (this.toString().search(/^-?[0-9]+$/) == 0 ) //回傳值為true/false
}

var myNum=1235.6;
alert (myNum.isInteger());
</script>