Issue link: https://read.uberflip.com/i/1146286
Index | 141 sprites, 11–13 Amazon, 108 CNN, 115 Google, 121 MSN, 124 Wikipedia, 130 Yahoo!, 132 D data: URL scheme, 13 main drawback, 14 Deferred Scripts (example), 50 deflate, 30 compression sizes, 31 delayed components, 38 DELETE request, 6 DHTML defined, 97 relationship between Web 2.0, DHTML, and Ajax, 96 DirectorySlash, 80, 81 DNS (Domain Name Service) aliases, 47 browser whitelist approach, 34 cache, 66 role of, 63 DNS lookups, 63–68 AOL, 113 browser perspective, 66–68 Firefox, 67 Internet Explorer, 66 caching and TTLs, 63–66 maximum TTL values sent to clients for top 10 U.S. web sites, 65 eBay, 117 factors affecting caching, 64 Keep-Alive, 67, 68 MSN, 124 MySpace, 128 reducing, 68 Dojo Compressor, 70 size reductions after gzip compression, 74 size reductions using, 71 Domain Name System (see DNS; DNS lookups) downloads parallel, 46–48 cost, 47 limiting, 46 scripts blocking, 48 Duplicate Scripts—10 Cached (example), 87 Duplicate Scripts—Cached (example), 86 Duplicate Scripts—Not Cached (example), 86 Dynamic Inlining (example), 61 E eBay DNS lookups, 117 ETags, 117 Expires header, 117 HTTP requests, 117 IFrames, 117 images, 117 percentage of time downloading, 4 performance recommendations, 116–119 scripts, 119 (see also top 10 U.S. web sites) Entity tags (see ETags) ETags, 35, 89–95 conditional GET requests, 8 defined, 89 eBay, 117 effectiveness of proxy caches, 92 example of component with changing ETag, 94 format for Apache 1.3 and 2.x, 92 format for IIS, 92 MSN, 124 options, 93 problem with, 91 removing, 93 top 10 U.S. web sites, 94–95 YouTube, 137 event handlers, 53 example, 53 Everything Gzipped (example), 35 examples Cacheable External JS and CSS, 58 CDN, 20 Combined Scripts, 16 CSS at the Bottom, 39 CSS at the Top, 41 CSS at the Top Using @import, 41 CSS Flash of Unstyled Content, 43 CSS Sprites, 13 Deferred Scripts, 50 Duplicate Scripts—10 Cached, 87 Duplicate Scripts—Cached, 86 Duplicate Scripts—Not Cached, 86 Dynamic Inlining, 61 Event Handler, 53 Everything Gzipped, 35