<input name=‘nameInput’  type=‘text’ value=’{{name}}’ placeholder=’{{name_placeholder}}’ placeholder-class=‘placeholder’ bindfocus=‘focusName’ bindblur=‘blurName’></input>

focusName: function(e){

this.setData({

name_placeholder:‘’

})

},

代码如上，开发者工具中是没有问题的，真机调试时，placeholder不会消失，如下图