JavaScript实现点击按钮显示当前时间

显示当前时间，点击按钮，显示当前系统时间

代码如下

<script>function tim() {var date = new Date();//当前系统时间var year = date.getFullYear();var month = date.getMonth();var de = date.getDate();var hours = date.getHours();var minutes = date.getMinutes();var seconds = date.getSeconds();var time = document.querySelector("span");time.innerHTML = year+'-'+month+'-'+de+' '+hours+':'+minutes+':'+seconds;}</script>