Performance Measures MCQ question and answer in javascript with solution

YSlow for PhantomJS introduces new output formats for automated test frameworks: TAP (Test Anything Protocol) and JUnit.

Intially, YSlow was an extension of Firefox.

For a deeper analysis of a page’s web performance you can use YSlow.

There are totally 23 rules in the ruleset of YSlow (V2) namely :
1. Minimize HTTP Requests
2. Use a Content Delivery Network
3. Avoid empty src or href
4. Add an Expires or a Cache-Control Header
5. Gzip Components
6. Put StyleSheets at the Top
7. Put Scripts at the Bottom
8. Avoid CSS Expressions
9. Make JavaScript and CSS External
10. Reduce DNS Lookups
11. Minify JavaScript and CSS
12. Avoid Redirects
13. Remove Duplicate Scripts
14. Configure ETags
15. Make AJAX Cacheable
16. Use GET for AJAX Requests
17. Reduce the Number of DOM Elements
18. No 404s
19. Reduce Cookie Size
20. Use Cookie-Free Domains for Components
21. Avoid Filters
22. Do Not Scale Images in HTML
23. Make favicon.ico Small and Cacheable

It is mandatory to run FireBug before running YSlow.

The YSlow for Mobile works as bookmaklet.

A content delivery network (CDN) allows you to distribute your static assets like images, JavaScript files and stylesheets to geographically distributed servers. This gets the content of your page to your user’s browser faster.

In a for loop, the initialization, the test, and the update are the three crucial manipulations of a loop variable.

If you want to run tests on web sites that are not publicly available—like a QA or development environment, or if you can only have your test results stored on your own servers because of legal or other reasons, then installing your own private instance of WebPagetest is the way to go.

In the Auth tab you can specify credentials to use if the web site uses HTTP authentication for access.