软件简介

On-Demand Javascript Plugin aka “Lazy Loading”

Download Javascript as and when required, instead of downloading it all on
page load. This is a “lazy loading” approach applied to Javascript, and has
several benefits…

• Initial page load is faster.
• Overall bandwidth usage is less, since only Javascript that’s required is used.
• Deployment is easier as the code takes care of pulling in Javascript, with the coder only ensuring enough is there to kick the process off.
• You can produce snippets of Javascript on the fly - effectively sending back a kind of “behaviour message” advising the browser on its next action. This is a variant of the core pattern described at the end of this section.
• You can bypass the standard “same-domain” policy that normally necessitates a Cross-Domain Proxy. Provided a server exposes a segment of valid Javascript, it can be extracted by the browser.

AjaxPatterns - On-Demand Javascript