The load time of a webpage is a crucial factor for keeping the visitor on a webpage. Too long load times cause the visitor to quit the webpage because he expects a fast and responsive webpage. Yahoo published a comprehensive guide of webdevelopment best practices that, if applied, reduce load times of webpages enhancing your user’s experience.
Summary of hints for webdevelopment purposes:
- Minimize HTTP requests
Combining files reduces HTTP get requests (e.g. one single CSS/JS file, Image sprites instead of multiple single images). - Put stylesheets at the top, scripts at the bottom
Putting CSS files within <head> tag loads images faster and lets the browser render the webpage progressively. - Reduce DNS lookups
Every different hostname causes a DNS lookup request. Consolidate all files on one hostname to reduce the request count to 1 or use IP addresses instead of hostnames or domains - Minify JavaScript and CSS
“Compress” your JavaScript or CSS files by removing unneccessary content, e.g. comments and white spaces. Many web development frameworks (such as Ruby on Rails or CakePHP) ship their own compressing tool, but there are also third-party tools available that minify content on-the-fly. For example check out Minify.
The whole guide with far more best practices and hints is available here: http://developer.yahoo.com/performance/rules.html