Javascript VaR在基础.UTI.TouCH.JS中未定义

我在手机上尝试使用滑块时出错，滑块无法拖动。这是针对非本机版本的。滑块可以在桌面chrome、firefox、ie上使用，但不能在ipad safari上使用

 var touches = event.changedTouches,
          first = touches[0],
          eventTypes = {
            touchstart: 'mousedown',
            touchmove: 'mousemove',
            touchend: 'mouseup'
          },
          type = eventTypes[event.type],
          simulatedEvent
;

地基5.5.3通过基础轨道5.5.3

 var touches = event.changedTouches,
          first = touches[0],
          eventTypes = {
            touchstart: 'mousedown',
            touchmove: 'mousemove',
            touchend: 'mouseup'
          },
          type = eventTypes[event.type],
          simulatedEvent
;

控制台中的错误为：

 var touches = event.changedTouches,
          first = touches[0],
          eventTypes = {
            touchstart: 'mousedown',
            touchmove: 'mousemove',
            touchend: 'mouseup'
          },
          type = eventTypes[event.type],
          simulatedEvent
;

类型错误：在第133行基础上未定义触摸。UTI.Touc.js

 var touches = event.changedTouches,
          first = touches[0],
          eventTypes = {
            touchstart: 'mousedown',
            touchmove: 'mousemove',
            touchend: 'mouseup'
          },
          type = eventTypes[event.type],
          simulatedEvent
;

 var touches = event.changedTouches,
          first = touches[0],
          eventTypes = {
            touchstart: 'mousedown',
            touchmove: 'mousemove',
            touchend: 'mouseup'
          },
          type = eventTypes[event.type],
          simulatedEvent
;

这条线是什么

 var touches = event.changedTouches,
          first = touches[0],
          eventTypes = {
            touchstart: 'mousedown',
            touchmove: 'mousemove',
            touchend: 'mouseup'
          },
          type = eventTypes[event.type],
          simulatedEvent
;

first = touches[0],

---

在这样的多变量声明var语句中使用一个var，声明它然后在同一个语句中使用它是否有效？这就是问题所在吗

我认为在使用较旧版本的jQuery时会出现这个问题。请参见

它是有效的。因此，似乎没有定义event.changedTouches。

 var touches = event.changedTouches,
          first = touches[0],
          eventTypes = {
            touchstart: 'mousedown',
            touchmove: 'mousemove',
            touchend: 'mouseup'
          },
          type = eventTypes[event.type],
          simulatedEvent
;