var Abstract = new Object();
代码解析及其使用方法Abstract（抽象类）是个空类，没有任何成员。
Object.extend源代码Object.extend = function(destination, source) {
for (var property in source) {
destination[property] = source[property];
}
return destination;
}
Object.extend(Object, {
inspect: function(object) {
try {
if (object === undefined) return 'undefined';
if (object === null) return 'null';
return object.inspect ? object.inspect() : object.toString();
} catch (e) {
if (e instanceof RangeError) return '...';
throw e;
}
},
toJSON: function(object) {
var type = typeof object;
switch(type) {
case 'undefined':
case 'function':
case 'unknown': return;
case 'boolean': return object.toString();
}
if (object === null) return 'null';
if (object.toJSON) return object.toJSON();
if (object.ownerDocument === document) return;
var results = [];
for (var property in object) {
var value = Object.toJSON(object[property]);
if (value !== undefined)
results.push(property.toJSON() + ': ' + value);
}
return '{' + results.join(', ') + '}';
},
keys: function(object) {
var keys = [];
for (var property in object)
keys.push(property);
return keys;
},
values: function(object) {
var values = [];
for (var property in object)
values.push(object[property]);
return values;
},
clone: function(object) {
return Object.extend({}, object);
}
});