Vue.directive('alterELDialogMarginTop'/*修改elementUI中el-dialog顶部的距离,传入值eg:{marginTop:'5vh'} */, {
          inserted(el, binding, vnode) {
                    el.firstElementChild.style.marginTop = binding.value.marginTop
          }
})

使用：

<el-dialog v-alterELDialogMarginTop="{marginTop:'5vh'}">