Page({ 
  data: { 
    sendInfo: \'\', 
    userMessage: \'\' 
},

<form bindreset="cleanInput">
     <input type="text" placeholder="输入新消息"  bindinput="bindMessage"></input>
     <button bindtap="sendMessage" formType="reset">发送 </button>
</form>

bindMessage: function(e) { 
    this.setData({ 
      userMessage: e.detail.value 
    })
 }

cleanInput: function() { 
    var setMessage = { sendInfo: this.data.userMessage }       
    this.setData(setMessage) 
}