https://developer.mozilla.org/en-US/docs/Web/API/History_API#Adding_and_modifying_history_entries
返回上一页并刷新：
<script> function back() { window.location.href=document.referrer;
}
</script>
返回上一页不刷新代码：
<script> function back() {
window.history.back(-1);
}
</script>
