{"id":449,"date":"2015-08-31T22:43:00","date_gmt":"2015-08-31T17:13:00","guid":{"rendered":"http:\/\/www.encoders.co.in\/blog\/?p=449"},"modified":"2025-04-29T14:56:45","modified_gmt":"2025-04-29T09:26:45","slug":"yslow-the-new-tool-for-page-speed","status":"publish","type":"post","link":"https:\/\/www.encoders.co.in\/blog\/seo\/yslow-the-new-tool-for-page-speed","title":{"rendered":"Yslow – The New Tool For Page Speed"},"content":{"rendered":"

YSlow<\/strong> analyzes web pages and suggests ways to improve their performance based on a set of rules for high \"download\"performance web pages.<\/h3>\n

It tell us why the page is slow based on\u00a0Yahoo!’s rules for high performance web sites<\/p>\n

 <\/p>\n

Top Features are :-<\/strong><\/h3>\n
    \n
  • It Grades web page based on one of three predefined rule set;<\/li>\n
  • It gives\u00a0suggestions for improving the \u00a0performance;<\/li>\n
  • It Summarizes the all\u00a0components of the web page;<\/li>\n
  • It gives\u00a0statistics about the web page;<\/li>\n<\/ul>\n

    The tool is available for all major browsers like<\/strong><\/h3>\n

    Firefox
    \nChrome
    \nMobile\/Bookmarklet
    \nOpera
    \nSafari<\/p>\n

    YSlow’s web page analysis is based on the 23 Rules there are as follows:-<\/strong><\/h3>\n

    Minimize HTTP Requests
    \nUse a Content Delivery Network
    \nAvoid empty src or href
    \nAdd an Expires or a Cache-Control Header
    \nGzip Components
    \nPut StyleSheets at the Top
    \nPut Scripts at the Bottom
    \nAvoid CSS Expressions
    \nMake JavaScript and CSS External
    \nReduce DNS Lookups
    \nMinify JavaScript and CSS
    \nAvoid Redirects
    \nRemove Duplicate Scripts
    \nConfigure ETags
    \nMake AJAX Cacheable
    \nUse GET for AJAX Requests
    \nReduce the Number of DOM Elements
    \nNo 404s
    \nReduce Cookie Size
    \nUse Cookie-Free Domains for Components
    \nAvoid Filters
    \nDo Not Scale Images in HTML
    \nMake favicon.ico Small and Cacheable<\/p>\n

    How it works<\/strong><\/h3>\n

    YSlow works in three phases to generate its results.<\/p>\n

    YSlow crawls the DOM to find all the components (images, scripts, stylesheets, etc.) in the page.
    \nAfter crawling the DOM, YSlow loops through Firebug’s Net Panel components and adds those to the list of components already found in the DOM
    \nYSlow gets information about each component: size, whether it was gzipped, Expires header, etc. YSlow gets this information from Firebug’s Net Panel if it’s available.
    \nIf the component’s information is not available from Net Panel (for example, the component was read from cache or it had a 304 response) YSlow makes an XMLHttpRequest to fetch the component and track its headers and other necessary information.
    \nYSlow takes all this data about the page and generates a grade for each rule, which produces the overall grade.<\/p>\n","protected":false},"excerpt":{"rendered":"

    YSlow analyzes web pages and suggests ways to improve their performance based on a set of rules for high performance […]<\/p>\n","protected":false},"author":1,"featured_media":1586,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[1],"tags":[],"class_list":["post-449","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-seo"],"_links":{"self":[{"href":"https:\/\/www.encoders.co.in\/blog\/wp-json\/wp\/v2\/posts\/449","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.encoders.co.in\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.encoders.co.in\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.encoders.co.in\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.encoders.co.in\/blog\/wp-json\/wp\/v2\/comments?post=449"}],"version-history":[{"count":3,"href":"https:\/\/www.encoders.co.in\/blog\/wp-json\/wp\/v2\/posts\/449\/revisions"}],"predecessor-version":[{"id":454,"href":"https:\/\/www.encoders.co.in\/blog\/wp-json\/wp\/v2\/posts\/449\/revisions\/454"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.encoders.co.in\/blog\/wp-json\/wp\/v2\/media\/1586"}],"wp:attachment":[{"href":"https:\/\/www.encoders.co.in\/blog\/wp-json\/wp\/v2\/media?parent=449"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.encoders.co.in\/blog\/wp-json\/wp\/v2\/categories?post=449"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.encoders.co.in\/blog\/wp-json\/wp\/v2\/tags?post=449"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}