Increase Page Speed and YSlow Grade

Question

I've cheked my MyBB forum in gtmetrix.com and gave this performance report:

http://gtmetrix.com/reports/www.forum.joorchin.net/TdxokjnO

Now I have many question to increase the Page Speed and YSlow Grade.

1. How can I defer the parsing of javaScripts?
2. How can I remove query string from static resources?
3. How can I cache the .swf and .js files? (Leverage browser caching)
4. How can I increase the Recommendations score in YSlow tab? (Medium and High PRIORITY)?

Answer 1

1- I think by defering parsing the javascript, they mean by putting all javascript at the end, or loading javascript asynchronously. Basically when a browser sees a script tags, it stops rendering the page until the javascript is interpreted in the script tag. Thats why its suggested to place all javascript at the end of a html page. you may or may need to change your code/js to handle this.

3 For caching .swf / .js files , if you are using Apache enable the expires module and set the revelant expires headers for the same

Answer 2

Rather than complicate your JS loading just merge them into one JS file and minify it (if possible). Do the same thing with your CSS so you are only requesting one JS file and one CSS file per page load.

Then use Apache to control the cache headers for all resource types by adding these Apache settings to either .htaccess or http.conf.

If you have an image heavy page design you may also look into using image sprites to reduce the number of images being retrieved from the server. Also make sure your images are compressed (i.e. smaller KB size) using a good web image processing tool like Fireworks, Photoshop, etc.

The majority of performance issues are related to the number of HTTP requests being made. You are right to ask about caching, but the initial page load (ie. before the cache is filled) is also important as it's the first impression a visitor will get of your site.