set up automatic modification/update time for your website

If you want to make the "last updated" info on your website automatically generated, you may use these codes:

the script tag should look like <script type="text/javascript">

also it is preferable to use the dom to insert content into the page, not document.write.

in the head:

PHP:

<script type="text/javascript">onload = function(){
    document.getElementById("lastModified").innerHTML = "Page last changed " + document.lastModified.split(" ")[0];
}</script>

later on in the body:

HTML:

<span id="lastModified"></span>

good read: http://www.quirksmode.org/js/lastmod.html

These are copied from here: https://forums.techguy.org/threads/how-can-i-get-an-automatic-last-updated-in-my-web-page.693929/