用于跨页面共享实用程序方法的共享单例模式

Posted 2021-02-26

/* A similar pattern to the module pattern is the “shared singleton” — create a singleton object for an application that can be used to share properties or methods between pages or inline frames.
 
Here’s the start of a “my.js” script that every page or frame in an application could share: */
 
if (typeof parent.my != “undefined”) {
var my = parent.my; // shared singleton
} else {
 
var my = {};
 
my.something …
 
}
 
/* The “parent” bit is so that the script can be used with iframes and still
retain a reference to the same “my” instance. If a page is at the top, then parent points to itself.
 
Every page or frame that imports “my.js” can share properties or methods with any other page. */