What influences the loading of a web page?
There are a great many things that influence the loading of a web page.
The obvious ones are:
- Size and number of images on page. More images means more stuff to download and render on screen.
- Size of the HTML on the page. Just like above, the HTML markup has to be downloaded from the web server before the page can be displayed.
- Large Flash/Silverlight animations and files. Big files = longer download.
- The download speed of the end user's internet connection. Slow connection translated to longer loading speed (not much you can do about this)
- Bandwidth of the hosting facility that manages the server for the web page. Same as the first, but on the sending end.
Additionally, things one may not think about that effect loading of a web page:
- Size and number of script and stylesheet files. Larger, non-minified files take longer to download and parse/render/execute.
- Large amounts of complex scripting on the page. The harder the browser has to work to render the page, the longer it will appear to load.
- A large number of errors in the structure of the HTML. The more the browser has to compensate or 'fix' these errors to display the content, the longer the page takes to load.
- Load on the web server hosting the web page. The harder the web server has to work, the slow it is to respond to requests and serve out content.
- Load in the database server. If your website draws content from a database, the harder the database server has to work, the slower it is going to respond to requests from the web server.
- Load on off-site content providers. If to draw content from another provider (website, RSS feed, etc), more time is required to get the data from their system to you, then to the user.
Some rare and obscure things that can effect page load time:
- DNS resolution bottlenecks
- Poorly made end point hardware at the user's location
- Mis-configured proxy or firewall hardware/software
- Mis-configured DNS server
- Mis-configured DNS records
- Mis-configured web server software