layui输入框只允许输入中文且判断长度的例子

<label class="layui-form-label">老师昵称</label>
<div class="layui-input-block layui-width21em">
 <input id="userName" name="userName" placeholder="请输入昵称" class="layui-input"
 aulete="off">
 <span style="color:red">(20个字符或者10个中文字)</span>
</div>

 form.verify({
 clength: function (value) {
   var i,sum; 
  sum=0; 
  for(i=0;i<value.length;i++){ 
  if ((value.charCodeAt(i)>=0) && (value.charCodeAt(i)<=255)) 
   sum=sum+1; 
  else 
   sum=sum+2; 
  } 
   if (sum > 200) {
    return '老师简介最多只能200个字符或者100个中文字';
   }
  },
  nlength: function (value) {
  var i,sum; 
  sum=0; 
  for(i=0;i<value.length;i++){ 
  if ((value.charCodeAt(i)>=0) && (value.charCodeAt(i)<=255)) 
   sum=sum+1; 
  else 
   sum=sum+2; 
  } 
   if (sum > 20) {
    return '老师昵称最多只能20个字符或者10个中文字';
   }
  }
 });
 });|

 <label class="layui-form-label">课程介绍</label>
 <div class="layui-input-block">
 <textarea class="layui-textarea" style="height:200px;width:800px" lay-verify="required" name="content" placeholder="请输入课程介绍"
 th:text="${swCourse.content}"></textarea><span style="color:red">(字符数控制在100汉字以内，且只能上传文字)</span>
 </div>
 </div>| 

layui.use([ ‘layer', ‘jquery', ‘form', ‘upload', ‘laytpl' ], function() {
 var $ = layui.jquery;
 var layer = layui.layer;
 var laytpl = layui.laytpl;
 var form = layui.form, upload = layui.upload;
 //自定义验证规则
 form.verify({
 length: function (value) {
   if(value.length > 20){
   return '课程名称最多只能20个字';
   }
  },
  characters:function(v){
   var numasc = 0;
    var charasc = 0;
    var otherasc = 0;
  for (var i = 0; i < v.length; i++) {
     var asciiNumber = v.substr(i, 1).charCodeAt();
     if (asciiNumber >= 48 && asciiNumber <= 57) {
      numasc += 1;
     }
     if ((asciiNumber >= 65 && asciiNumber <= 90)||(asciiNumber >= 97 && asciiNumber <= 122)) {
      charasc += 1;
     } 
     if ((asciiNumber >= 33 && asciiNumber <= 47)||(asciiNumber >= 58 && asciiNumber <= 64)||(asciiNumber >= 91 && asciiNumber <= 96)||(asciiNumber >= 123 && asciiNumber <= 126)) {
      otherasc += 1;
     }
    }
  if(numasc > 0 || charasc>0 || otherasc>0) {
     return "只能输入中文";
    }
  } ,
 clength: function (value) {
   var i,sum; 
  sum=0; 
  for(i=0;i<value.length;i++){ 
  if ((value.charCodeAt(i)>=0) && (value.charCodeAt(i)<=255)){ 
   sum=sum+1; 
  }else{
   sum=sum+2; 
  }
  } 
   if (sum > 200) {
    return '课程介绍最多只能输入100个中文字';
   }
  }
 });|