Vue组件：一键回顶。基于 Tailwind CSS

backTop2.vue

<template>
  <Transition>
    <button
      class="h-16 w-16 shadow-xl rounded-full border-none btn-primary fixed bottom-10 right-10 z-50"
      v-show="btnFlag"
      @click="backTop"
    >
      <div>
        <svg
          t="1678205587482"
          class="w-8 h-8 p-1 m-4"
          viewBox="0 0 1024 1024"
          version="1.1"
          xmlns="http://www.w3.org/2000/svg"
          p-id="8535"
          width="200"
          height="200"
        >
          <path
            fill="#ffffff"
            d="M890.5 755.3L537.9 269.2c-12.8-17.6-39-17.6-51.7 0L133.5 755.3c-3.8 5.3-0.1 12.7 6.5 12.7h75c5.1 0 9.9-2.5 12.9-6.6L512 369.8l284.1 391.6c3 4.1 7.8 6.6 12.9 6.6h75c6.5 0 10.3-7.4 6.5-12.7z"
            p-id="8536"
          ></path>
        </svg>
      </div>
    </button>
  </Transition>
</template>

<script setup lang="ts">
const btnFlag = ref(false)
const scrollTop = ref(0)

onMounted(() => {
  window.addEventListener('scroll', scrollToTop)
})

onUnmounted(() => {
  window.removeEventListener('scroll', scrollToTop)
})

function backTop() {
  document.documentElement.scrollTop = document.body.scrollTop = 0
}

function scrollToTop() {
  scrollTop.value =
    window.pageYOffset ||
    document.documentElement.scrollTop ||
    document.body.scrollTop
  if (scrollTop.value > 400) {
    btnFlag.value = true
  } else {
    btnFlag.value = false
  }
}
</script>

<style scoped>
.v-enter-active,
.v-leave-active {
  transition: opacity 0.3s ease;
}

.v-enter-from,
.v-leave-to {
  opacity: 0;
}
</style>