Modern browsers cache web pages. However, there is currently a serious problem: pages remain unused for months, even years. In other words, if a user accesses your page, it is cached and never reloaded, even after complete page changes, including server changes, leading to errors.
Without the clear cache javascript code, your pages won't reload for months, even years, leading to login system failures or preventing your website or system from updating.
f you change the login page, for example by altering a captcha, or change the code of your index or default page, it will not load for people who have already accessed your site or system at least once, because the browser does not understand that there has been an update, and loads the old, outdated page.
The codes that were used to clear the browser cache no longer work; they've become obsolete. The browser simply ignores these codes and opens the cache. Even if you completely refresh your homepage, or even switch servers, or change the website, if the user has accessed your page once, they will open the cached page forever.
Examples of Code That Doesn't Work:
<meta http-equiv = 'cache-control' content = 'no-cache'>
<meta http-equiv = 'expires' content = '0'>
<meta http-equiv = 'pragma' content = 'no-cache'>
<script>
location.reload(true);
</script>