Friday, February 10, 2012

Performance Engineering -Unleash with YSLow Tool/Jslint

A Quick refresher on web page performance Tuning
YSlow is integrated into the Firebug web development tool for Firefox.
Note: YSlow is not integrated into Firebug Lite for Internet Explorer at this point in time.
1. Download and install Firefox:
http://www.mozilla.com/en-US/firefox/personal.html
2. Download and install Firebug: http://getfirebug.com/
Note: Cannot be downloaded from IE
3. Download and install YSlow
https://addons.mozilla.org/en-US/firefox/addon/5369

The parameter to test the web page for performance are listed Below

1. Make Fewer HTTP Requests
2. Compress Components with gzip
3. Minify JavaScript and CSS
4. Configure entity tags (ETags)
5. Reduce the number of DOM elements
6. Put CSS at top 7. Make JavaScript and CSS external
8. Avoid URL redirects
9. Make Ajax cacheable
10. Avoid HTTP 404 (not found) errors
11. Add Expires Headers
12. Put JavaScript at bottom
13. Remove Duplicate JavaScript and CSS
14. Use Get for Ajax Request
15. Reduce cookie size

The YSLow will list following details
The tool will show the details for each file:
· URL,
· when it expires
· the response time in ms to download the file
· ETAG
The bench mark for page performance:

· Page Size: 100K-150K
· Response Time: Less than 3000 ms in total

Additional Tool





  1. JSLint


  2. All JS


  3. All JS Beatified


  4. All CSS


  5. All Smash.it


  6. All Js Minified



Hope this help.
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