js-xss/README.md

过滤XSS攻击
======

## 安装

**npm install xss**


## 原理

通过标签白名单及属性白名单来过滤HTML标签，同时对包含特殊字符的属性值进行处理。默认配置可过滤大多数的XSS攻击代码，可根据实际应用场景来定制白名单及过滤方法。


## 使用方法

```javascript
var xss = require('xss');
// 使用默认的HTML白名单
console.log(xss('<script>alert("fff");</script>'));
// 修改默认的白名单
xss.whiteList.em = ['style']; //添加或更新一个 tag 到白名单
delete xss.whiteList.em; //从白名单删除一个 tag
// 指定HTML白名单
var whiteList = {
	tag: ['attribute1', 'attribute2']	// 允许的属性
};
console.log(xss('<script>alert("fff");</script>', whiteList));
// 请参考默认的白名单：xss.whiteList

// 过滤指定属性的值，参考默认的 xss.onTagAttr
console.log(xss('<a href="javascript:ooxx">abc</a>', function (tag, attr, value) {
	if (tag === 'a' && attr === 'href') {
		if (value.substr(0, '11') === 'javascript:') {
			return '#';
    	}
  	}
}));
```


## 函数调用格式

* 使用默认配置： xss('要过滤的HTML代码');

* 使用自定义配置： xss('要过滤的HTML代码', 白名单, 过滤属性值函数); (可仅指定白名单或过滤属性值函数作为第二个参数)

白名单格式：

```
{
	'小写标签名':   ['允许出现的属性名（小写）']
}
```

过滤属性值函数格式：

```
/**
 * @param {string} tag 标签名
 * @param {string} attr 属性名
 * @param {string} value 属性值
 * @return {string} 若要修改此属性值，返回新属性值即可，否则不用返回值
function (tag, attr, value) {
	// ...
}
```

## 测试

单元测试：**npm test**

在线测试：运行目录中的**cli.js**，可在命令行中输入HTML代码，并看到过滤后的代码


## 性能

解析速度为**6.26MB/s**，而另外一个**validator**模块的xss()函数速度仅为**2.82MB/s**。

测试代码参考**benchmark**目录


## 授权协议

基于MIT协议发布：

```
Copyright (c) 2012 Lei Zongmin(雷宗民) <leizongmin@gmail.com>
http://ucdok.com

The MIT License

Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:

The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
```