YSlow is a nice addon to determine page performance

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YSlow is a nice addon to determine page performance

Welcome to CodeSpread!

YSLOW is one handier tool for a developer. It is used to analyze web pages and get it tested on the rules identified which are explained below. I like the name “YSlow”as it more or less poses a question “why slow?”. It is available as an add-on to most of the popular browsers like Firefox,Chrome,Safari etc. or can be downloaded from yslow.org.

Source: yslow.org

Yahoo!’s Exceptional Performance team has identified 34 rules that affect web page performance. YSlow’s web page analysis is based on the 23 of these 34 rules that are testable.

• Minimize HTTP Requests

• Use a Content Delivery Network.

• Avoid empty src or href.

• Add an Expires or a Cache-Control Header.

• Gzip Components.

• Put StyleSheets at the Top.

• Put Scripts at the Bottom.

• Avoid CSS Expressions.

• Make JavaScript and CSS External.

• Reduce DNS Lookups.

• Minify JavaScript and CSS.

• Avoid Redirects.

• Remove Duplicate Scripts.

• Configure ETags.

• Make AJAX Cacheable.

• Use GET for AJAX Requests.

• Reduce the Number of DOM Elements.

• No 404s.

• Reduce Cookie Size.

• Use Cookie-Free Domains for Components.

• Avoid Filters.

• Do Not Scale Images in HTML.

• Make favicon.ico Small and Cacheable.

I know we have been lazy in optimizing codespread.com but in some way, we are lucky that we can run yslow against it and catch many test results as failures to explain them here. Let’s run it on codespread.com.

First, we see the default screen of YSlow which gives us a slight idea about its operation.

yslow

yslow

Here, we can see a dropdown to select a ruleset of tests against which we would like run our website. We have 3 options available but we will select only the default option here to test the website against the latest version of ruleset available.

yslowreport

yslowreport

Overall, we have scored a D grade and a performance score of 70. Good news is, we have A grade in one or two instances like

• Avoid empty src or href.

• Put CSS at top.

Alert news is, F grade in instances like

• Make fewer HTTP requests.

• Use a CDN.

YSlow goes a step further and tells us the exact number of files and their types which are contributing to excess HTTP requests, plus what needs to be done to make it faster. That is the beauty of YSlow, It can make even an amateur understand the exact cause and also provides the suggestions for improvement. Here, we also see that not all rules are applicable in general case so we just need to look for the rules applicable to us and work on the suggestions.

YSlow is an awesome tool and also free. Just try it and share your experience.

Author: swatiS

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0 Comments

  1. nice superb explaination

    Post a Reply
  2. thanks for the tutorial
    I am having a problem.
    The feature “Create SQL server database” isn’t available , I can’t select it.
    Can you help, please ?

    Post a Reply

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