/**
* 构建类之间的继承关系
*
* @param {Function} subClass 子类函数
* @param {Function} superClass 父类函数
*/
function inherits(subClass, superClass) {
var subClassProto = subClass.prototype;
var F = new Function();
F.prototype = superClass.prototype;
subClass.prototype = new F();
subClass.prototype.constructor = subClass;
extend(subClass.prototype, subClassProto);
}
/**
* 对象属性拷贝
*
* @param {Object} target 目标对象
* @param {Object} source 源对象
* @return {Object} 返回目标对象
*/
function extend(target, source) {
for (var key in source) {
if (source.hasOwnProperty(key)) {
var value = source[key];
if (typeof value !== 'undefined') {
target[key] = value;
}
}
}
return target;
}