<script type="text/javascript">document.write(new Date().getFullYear());</script>

对于React.js，下面是我在页脚工作的方法…

render() {
    const yearNow = new Date().getFullYear();
    return (
    <div className="copyright">&copy; Company 2015-{yearNow}</div>
);
}

在网站上打印当前年份的最短方法

只需使用这段代码

<?php echo date('Y'); ?>

这是我能想到的使用纯JavaScript的最佳解决方案。您还可以在CSS中为元素设置目标样式。只要把年份加进去，它就会自动更新。

//Wait for everything to load first
window.addEventListener('load', () => {
    //Wrap code in IIFE 
    (function() {
        //If your page has an element with ID of auto-year-update the element will be populated with the current year.
        var date = new Date();
        if (document.querySelector("#auto-year-update") !== null) {
            document.querySelector("#auto-year-update").innerText = date.getFullYear();
        }
    })();
});

几年后，当我做其他事情时，我被提醒Date()(没有new)返回一个字符串，并且一种比我原来的短一个字符的方式出现在我面前:

<script>document.write(/\d{4}/.exec(Date())[0])</script>

Date()中字符串的第一个四位数序列被指定为年份。(当我最初的答案发布在下面时，这并不是特定的行为——尽管这很常见。)

当然，这个解的有效期仅为7979年(截至2021年撰写本文时)，因为在10000年，它将显示“1000”而不是“10000”。

你已经要求一个JavaScript解决方案，所以这里是我可以得到它的最短:

<script>document.write(new Date().getFullYear())</script>

这在我使用过的所有浏览器中都适用。

我是怎么做到的:

You can just call getFullYear directly on the newly-created Date, no need for a variable. new Date().getFullYear() may look a bit odd, but it's reliable: the new Date() part is done first, then the .getFullYear(). You can drop the type, because JavaScript is the default; this is even documented as part of the HTML5 specification, which is likely in this case to be writing up what browsers already do. You can drop the semicolon at the end for one extra saved character, because JavaScript has "automatic semicolon insertion," a feature I normally despise and rail against, but in this specific use case it should be safe enough.

需要注意的是，这只适用于启用JavaScript的浏览器。理想情况下，这最好是作为每年一次的离线批处理作业(*nix上的sed脚本等)来处理，但如果您想要JavaScript解决方案，我认为这是最简单的解决方案。(现在我已经去挑战命运了。)

However, unless you're using a server that can only provide static files, you're probably better off doing this on the server with a templating engine and using caching headers to allow the resulting page to be cached until the date needs to change. That way, you don't require JavaScript on the client. Using a non-defer/async script tag in the content also briefly delays the parsing and presentation of the page (for exactly this reason: because the code in the script might use document.write to output HTML).

<script type="text/javascript">document.write(new Date().getFullYear());</script>