<!doctype html>
<title>blur</title> <script> var input = document.getElementById('fina__amount'); input.onblur = function check(){ var reg = /^\d+(?=\.{0,1}\d+$|$)/; if(!(reg.test(input.value))){ input.style='border:1px solid red'; alert('金额有误,请重新输入'); }else{ input.style='border: 1px solid #d5d5d5'; }; }/*Jquery方法