js 校验input框中输入数字是否为数字，并动态提示

input输入框
<#form:input id="accountChange" path="accountChange" maxlength="5" class="form-control digits" οninput="accountChangeFunction()"/>
<#form:input id="accountTotal" path="accountTotal" maxlength="5" class="form-control hidden"/>
<#form:input id="accountUsed" path="accountUsed" maxlength="5" class="form-control hidden"/>
提示信息label

原因填写：
<#form:textarea id="accountChangeReason" disabled="false" path="accountChangeReason" rows="1" maxlength="1000" class="form-control"/>
script代码：
function accountChangeFunction(){
   var label = document.getElementById("modifyAccount");
   var accountTotal = document.getElementById("accountTotal").value;
   var accountChange = document.getElementById("accountChange").value;
   var regular = /^[0-9]\d*$/;
   if(regular.test(accountChange))
   {
      var total = parseInt(accountTotal)+parseInt(accountChange);
      label.innerText = "修改后："+total+"个";
      $('#accountChangeReason').removeAttr("disabled");
   }
   else
   {
      label.innerText = "请输入正整数";
   }
};