html代码
<form id="myForm" method="post" action="" onsubmit="return check()"> ????<input id="num" type="number" onkeyup="this.value=this.value.replace(/\D/g,‘‘)" ??????????????????onafterpaste="this.value=this.value.replace(/\D/g,‘‘)" > ???<input type="submit" id="submit" value="提交"></form>
JS代码
<script> ???function check() { ???????var num= document.getElementById("num").value; ???????if (num== null || num === ‘‘) { ???????????alert("请填写数字"); ???????????return false; ???????} ???????return true; ???}</script>
提交form前使用JS先进行验证
原文地址：https://www.cnblogs.com/wangwg1994/p/8570068.html