<input type="text" lay-verify="digital" placeholder="请输入数字">
<button type="button" class="layui-btn layui-btn-norma" lay-submit lay-filter="submit_button">提交</button>

form.verify({
 //数组的两个值分别代表：[正则匹配、匹配不符时的提示文字]
 ,digital: [
  /^[0-4]*$/
 ,'请填入0-4的分数'
 ] 
}); 

layui.use(['form'], function () {
  var form = layui.form;
  //要放在form.on外面，千万不能放在提交步骤中，否则会不触发
  form.verify({
   //数组的两个值分别代表：[正则匹配、匹配不符时的提示文字]
   digital: [
    /^[0-4]*$/
    ,'请填入0-4的分数'
   ]
  });
  form.on("submit(submit_button)", function (data) {
   return false;
  });
 });