原生js阻止冒泡

 <script>        
   
 var span = document.querySelector('.txt');        
 
 
 
        span.onclick = function(e) {            
        // 阻止事件冒泡            
        e.stopPropagation();
            console.log('span阻止了冒泡')
        }    
        
  </script>