let id = item.id
if ($.inArray(id, this.selectedData) === -1) {
   this.selectedData.push(id)
} else {
   this.removeByValue(this.selectedData, id)
}

//删除重复元素
function removeByValue (arr, val) {
     for (var i = 0; i < arr.length; i++) {
       if (arr[i] === val) {
          arr.splice(i, 1)
          break
       }
     }
}