<!--CSS-->
 <style>
     .active{
         pointer-events: none;
     }
 </style>
 <!--HTML-->
 <ul>
     <li><a class="tab"></a></li>
     <li><a class="tab active"></a></li>
     <li><a class="tab"></a></li>
 </ul>

<!--CSS-->
 .j-pro{
     pointer-events: none;
 }
 <!--HTML-->
 <button r-model={this.submit()} r-class={{"j-pro": flag}}>提交</button>
 <!--JS-->
 submit: function(){
     this.data.flag = true;
     this.$request(url, {
         // ...
         onload: function(json){
             if(json.retCode == 200){
                 this.data.flag = false;
             }
         }.bind(this)
         // ...
     });
 }

<!--CSS-->
 .layer{
     backround: linear-gradient(180deg, #fff, transparent);

 }
 .j-pro{
     poninter-events: none;
 }
 <!--HTML-->
 <ul>
     <li class="layer j-pro"></li>
     <li class="item"></li>
     <li class="item"></li>
     <li class="item"></li>
 </ul>