例一

合并 settings 和 options，修改并返回 settings

var settings = { validate: false, limit: 5, name: "foo" };
var options = { validate: true, name: "bar" };
jQuery.extend(settings, options);

结果 settings == { validate: true, limit: 5, name: "bar" }

 

例二

合并 defaults 和 options, 不修改 defaults。
var empty = {};
var defaults = { validate: false, limit: 5, name: "foo" };
var options = { validate: true, name: "bar" };
var settings = jQuery.extend(empty, defaults, options);

 

结果
settings == { validate: true, limit: 5, name: "bar" }
empty == { validate: true, limit: 5, name: "bar" }

 

转自jQuery帮助文档