jQuery.extend
extend
jQuery.extend = jQuery.fn.extend = function() {
var target = arguments[0] || {}, // 第一个参数是目标
i = 1, length = arguments.length, deep = false, options;
if (target.constructor == Boolean) {// 第一个参数是bool型的
deep = target;// 深度copy
target = arguments[1] || {};// target指向第二个参数
i = 2;
}
// target 是string 型的或?
if (typeof target != "object" && typeof target != "function")
target = {};
if (length == i) {// 只有一个参数?或deep copy 时,两个参数
target = this;// 目标为this
--i;
}
for (;i < length; i++)
if ((options = arguments[i]) != null)
for (var name in options) {
var src = target[name], copy = options[name];
if (target === copy)// 防止死循环
continue;
// 深度copy处理,最深为元素
if (deep && copy && typeof copy == "object" && !copy.nodeType)
target[name] = jQuery.extend(deep, src
|| (copy.length != null ? [] : {}), copy);
else if (copy !== undefined)// 直接copy
target[name] = copy;
}
return target;
};
有人批评(好像是fins)prototype,说它是一个extend支撑半边天。对于Jquery而言,也是一个extend支持了一边天。Jquery提供了extend对jquery进行扩展。jQuery.fn.extend是对jquery对象进行扩展。jQuery.extend是对jquery的静态方法进行扩展。它们是同一个方法。
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