正则表达式实例

<div class="qfverify">
 <input type="text"  onkeyup="inputIntReg(this)" placeholder="请输入充值预算">
 <p class="qfverify__font">请输入有效数字</p>
</div>
<script>
  function inputIntReg(obj) {
    var val = obj.value;
    var reg = /^(0|([1-9]\d*))$/;
    if(val.length > 0){
      if (reg.test(val)){
       $(obj).closest('.qfverify').removeClass('is-error')
      } else {
       $(obj).closest('.qfverify').addClass('is-error')
      }
    }else{
       $(obj).closest('.qfverify').removeClass('is-error')
    }
  }
</script>