Certain web servers, such as Apache on Unix systems, are case-sensitive regarding file names. For example, “london.jpg” cannot be accessed as “London.jpg”.
Conversely, other servers like Microsoft’s IIS are not case-sensitive. Thus, “london.jpg” can be accessed as “London.jpg”.
When employing a combination of upper and lowercase, it’s crucial to acknowledge this distinction.
Transitioning from a case-insensitive to a case-sensitive server can result in even minor discrepancies breaking your website.
To circumvent these issues, consistently employ lowercase file names!
HTML files are ideally given a .html extension (although .htm is permissible).
CSS files should end with a .css extension.
JavaScript files should conclude with a .js extension.