What are 404 Errors and what are the cause(s) of 404 Errors?
404 Errors occur when a user requests a web page that a server can't provide or that doesn’t exist. The 404 Error is compiled by the server and the error is then returned to the user's browser. The primary cause of 404 Errors are Universal Resource Location (“URL”) mistakes - URLs are web addresses by which users can identify and locate web components, such as specific web sites or web pages.
There are three key factors leading to URL mistakes:
- Syntax errors, arising from manual entry.
- Following an incorrect (or a broken) link.
- Following a link in an email, which was broken by an email server algorithm.
What do users see?
- When URL mistakes lead to 404 Errors, users (via their browser) receive a standard error message, which contains the following two components:
- The first component is an http status code. This code is read by the user's browser, and the code is derived from those used within the first web server, which was built by Tim Beners Lee. In addition, the first digit of status code '404' indicates that the requested web domain has been found. (The domain is a URL component that identifies a unique web site). In contrast, the last digit of status code '404' indicates that the requested page has not been found.
- Usually, the second component is a default error page.
What are the impacts of 404 errors on a visitors experience?
404 Errors are frequently disruptive. Very often, their lack of specificity disrupts a visitors use of a site. Research by the World Wide Web Consortium (“W3C”) suggests that 404 Errors reduce site usage by as much as 10%, impacting significantly upon any return on investment (“ROI”). Given the need to maximise web development budgets, particularly in the highly competitive small to medium sized business sector, ROI reductions (as a consequence of 404 Errors) are worth investigating. Nevertheless, 404 Errors needn't reduce either usage or ROI.
Why are default error pages problematic?
More often than not, a user experiences a 404 Error as a default error page. This is problematic, because:
- Default pages are often neither site-branded nor request specific; they can be confusing.
- Default pages are often perceived as being stern. They may appear to be telling the user off for not having entered the address correctly.
Together these disrupt the user experience. Most users will not make a second attempt to find the requested page. Such problems can be addressed through the creation of a customised 404 Error page, which will replace the default, and which will contain both useful information and important links for the user.
What are the five essentials of a customised 404 Error page?
The five essential elements of a customised 404 Error page are:
- an appropriate error message and a contact link
- a site specific search box
- a link to the site's home page
- a link to the site map
- links to the site's main sections
404 Errors and Re-organising your site
If the primary cause of 404 Errors are URL mistakes, a secondary cause is site reorganisation, which can directly impact upon search engine performance. Site reorganisation leads to 404 Errors when existing pages are either renamed or removed. This breaks existing links to those pages, including existing search engine links.
W3C best practice guidance indicates a long term URL strategy – you should ensure your URLs remain as stable as possible. Nevertheless, if pages must be renamed or removed, page redirects should be established to prevent 404 Error problems. Such redirects use status codes (300 + codes). This would ensure that erroneous pages requests (from users) are redirected to pages that the web server can provide.
