scroll-view 的事件为什么都不能触发？

<scroll-view class=‘bb’ upper-threshold lower-threshold bindscrolltoupper=‘a’ bindscrolltolower=‘b’ scroll-top bindtap=‘a’scroll-y=“false” scroll-x=“false”  bindscrolltoupper=“” bindscrolltolower=“” bindscroll=“” scroll-into-view=“” scroll-top=“500”>

<scroll-view class=‘aa’ upper-threshold lower-threshold bindscrolltoupper=‘a’ bindscrolltolower=‘b’ scroll-top bindtap=‘b’ bindscroll=‘c’ >位置</scroll-view>

<image src=‘…/img/00.jpg’></image>

</scroll-view>  

//js

a:function(){

console.log(1)

},

b:function(){

console.log(2)

},

c: function () {

console.log(3)

},