ajax - 异步加载图像

Question

我已经阅读了 SEO 以异步方式进行一些 URL 访问是有好处的。我见过一些以这种方式加载图像的好页面，但我不确定花时间这样做是否值得。

我正在开发一个电子商务网站，当然，我需要它在 Google 中的位置尽可能好。对于我的产品目录和产品详细信息页面，我可以将其付诸实践，但正如我所说，我不知道这是否值得。

任何有经验的人都可以告诉我我应该还是不应该，以一种或另一种方式做这件事有哪些优点和缺点？

Answer 1

For SEO a good rule of thumb is that your page needs to be usable in three seconds from the time that a user clicks on your site in the search engine results pages (SERPs). After about three seconds users start turning back to look for something else. Google takes note of this user defection and sites slower than three seconds start to fall for the queries for which they were ranking.

You can use tools like the Firebug plugin for Firefox to measure your site speed. Access your site remotely using this plugin and look at the net tab to see how long it takes to get the page to the "onload" state.

Getting your site faster than three seconds doesn't seem to have much impact on search engine rankings. You may find that it increases user engagement and conversions in other ways though.

The specific technique of asynchronous images that you mention is just one in a large arsenal of things that you can do. Asynchronous images is most appropriate for images below the fold that users don't see without scrolling.

You should also consider other options such as:

• Image sprites
• Gzip compression on the server (mod_gzip)
• CDN services
• Compacting and minimizing HTML, JS, and CSS (using YUI Compressor or similar)
• Combining and inlining JS and CSS

Install browser plugins such as Google Page Speed that will examine your site and give you a whole list of relevant suggestions.