282 lines
7.6 KiB
JavaScript
282 lines
7.6 KiB
JavaScript
/**
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* 过滤XSS攻击
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*
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* @author 老雷<leizongmin@gmail.com>
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*/
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/*
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* 默认HTML标签白名单
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* 标签名=>属性列表
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*/
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var defaultWhiteList = {
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h1: ['style', 'class'],
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h2: ['style', 'class'],
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h3: ['style', 'class'],
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h4: ['style', 'class'],
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h5: ['style', 'class'],
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hr: ['style', 'class'],
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span: ['style', 'class'],
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strong: ['style', 'class'],
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b: ['style', 'class'],
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i: ['style', 'class'],
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br: [],
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p: ['style', 'class'],
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pre: ['style', 'class'],
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code: ['style', 'class'],
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a: ['style', 'class', 'target', 'href', 'title'],
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img: ['style', 'class', 'src', 'alt', 'title'],
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div: ['style', 'class'],
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table: ['style', 'class', 'width', 'border'],
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tr: ['style', 'class'],
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td: ['style', 'class', 'width', 'colspan'],
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th: ['style', 'class', 'width', 'colspan'],
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tbody: ['style', 'class'],
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ul: ['style', 'class'],
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li: ['style', 'class'],
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em: ['style'],
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cite: ['style'],
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section:['style', 'class'],
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};
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/**
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* 过滤属性值
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*
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* @param {string} tag 标签名
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* @param {string} attr 属性名
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* @param {string} value 属性值
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* @return {string} 若不需要修改属性值，不返回任何值
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*/
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var defaultOnTagAttr = function (tag, attr, value) {
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if (attr === 'href' || attr === 'src') {
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if (/\/\*|\*\//mg.test(value)) {
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return '#';
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}
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if (/^[\s"'`]*((j\s*a\s*v\s*a|v\s*b|l\s*i\s*v\s*e)\s*s\s*c\s*r\s*i\s*p\s*t\s*|m\s*o\s*c\s*h\s*a):/ig.test(value)) {
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return '#';
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}
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} else if (attr === 'style') {
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if (/\/\*|\*\//mg.test(value)) {
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return '#';
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}
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if (/((j\s*a\s*v\s*a|v\s*b|l\s*i\s*v\s*e)\s*s\s*c\s*r\s*i\s*p\s*t\s*|m\s*o\s*c\s*h\s*a):/ig.test(value)) {
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return '';
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}
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}
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};
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/**
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* 过滤非白名单的标签
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*
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* @param {string} tag 标签名
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* @param {string} html 标签HTML代码（包括属性值）
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* @param {object} options 更多属性：
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* position：在返回的HTML代码中的开始位置
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* originalPosition：在原HTML代码中的开始位置
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* isClosing：是否为闭合标签，如</a>
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* @return {string} 若不返回任何值，则默认替换<>为<>
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*/
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var defaultOnIgnoreTag = function (tag, html, options) {
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return noTag(html);
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};
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/**
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* 转换<>为< >
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*
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* @param {string} text
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* @return {string}
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*/
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var noTag = function (text) {
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return text.replace(/</g, '<').replace(/>/g, '>');
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};
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/**
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* XSS过滤
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*
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* @param {string} html 要过滤的HTML代码
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* @param {object} options 选项：whiteList, onTagAttr, onIgnoreTag
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* @return {string}
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*/
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exports = module.exports = function (html, options) {
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'use strict';
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options = options || {};
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var whiteList = options.whiteList || exports.whiteList;
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var onTagAttr = options.onTagAttr || exports.onTagAttr;
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var onIgnoreTag = options.onIgnoreTag || exports.onIgnoreTag;
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var rethtml = '';
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var lastPos = 0;
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var tagStart = false;
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var quoteStart = false;
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var currentPos = 0;
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/**
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* 过滤不合法的属性
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*/
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var filterAttributes = function (tagName, attrs) {
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tagName = tagName.toLowerCase();
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var whites = whiteList[tagName];
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var lastPos = 0;
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var _attrs = [];
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var tmpName = false;
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var hasSprit = false;
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var addAttr = function (name, value) {
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name = name.trim();
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if (!hasSprit && name === '/') {
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hasSprit = true;
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return;
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};
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name = name.replace(/[^a-zA-Z0-9_:\.\-]/img, '').toLowerCase();
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if (name.length < 1) return;
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if (whites.indexOf(name) !== -1) {
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if (value) {
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value = value.trim().replace(/"/g, '"e;');
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// 转换unicode字符 及过滤不可见字符
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value = value.replace(/&#([a-zA-Z0-9]*);?/img, function (str, code) {
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code = parseInt(code);
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return String.fromCharCode(code);
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});
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var _value = '';
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for (var i = 0, len = value.length; i < len; i++) {
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_value += value.charCodeAt(i) < 32 ? ' ' : value[i];
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}
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value = _value.trim();
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var newValue = onTagAttr(tagName, name, value);
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if (typeof(newValue) !== 'undefined') {
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value = newValue;
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}
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}
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_attrs.push(name + (value ? '="' + value + '"' : ''));
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}
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};
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for (var i = 0, len = attrs.length; i < len; i++) {
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var c = attrs[i];
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if (tmpName === false && c === '=') {
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tmpName = attrs.slice(lastPos, i);
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lastPos = i + 1;
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continue;
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}
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if (tmpName !== false) {
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if (i === lastPos && (c === '"' || c === "'")) {
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var j = attrs.indexOf(c, i + 1);
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if (j === -1) {
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break;
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} else {
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var v = attrs.slice(lastPos + 1, j).trim();
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addAttr(tmpName, v);
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tmpName = false;
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i = j;
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lastPos = i + 1;
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continue;
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}
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}
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}
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if (c === ' ') {
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var v = attrs.slice(lastPos, i).trim();
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if (tmpName === false) {
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addAttr(v);
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} else {
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addAttr(tmpName, v);
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}
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tmpName = false;
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lastPos = i + 1;
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continue;
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}
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}
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if (lastPos < attrs.length) {
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if (tmpName === false) {
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addAttr(attrs.slice(lastPos));
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} else {
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addAttr(tmpName, attrs.slice(lastPos));
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}
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}
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if (hasSprit) _attrs.push('/');
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return _attrs.join(' ');
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};
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/**
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* 检查标签是否合法
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*/
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var addNewTag = function (tag, end) {
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rethtml += noTag(html.slice(lastPos, tagStart));
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lastPos = end + 1;
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var spos = tag.slice(0, 2) === '</' ? 2 : 1;
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var i = tag.indexOf(' ');
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if (i === -1) {
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var tagName = tag.slice(spos, tag.length - 1).trim();
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} else {
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var tagName = tag.slice(spos, i + 1).trim();
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}
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tagName = tagName.toLowerCase();
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if (tagName in whiteList) {
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// 过滤不合法的属性
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if (i === -1) {
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rethtml += tag.slice(0, spos) + tagName + '>';
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} else {
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var attrs = filterAttributes(tagName, tag.slice(i + 1, tag.length - 1).trim());
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rethtml += tag.slice(0, spos) + tagName + (attrs.length > 0 ? ' ' + attrs : '') + '>';
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}
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} else {
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// 过滤不合法的标签
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var options = {
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isClosing: (spos === 2),
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position: rethtml.length,
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originalPosition: currentPos - tag.length + 1
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};
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var tagHtml = onIgnoreTag(tagName, tag, options);
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if (typeof(tagHtml) === 'undefined') {
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tagHtml = noTag(tag);
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}
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rethtml += tagHtml;
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}
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};
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// 逐个分析字符
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for (var currentPos = 0, len = html.length; currentPos < len; currentPos++) {
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var c = html[currentPos];
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if (tagStart === false) {
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if (c === '<') {
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tagStart = currentPos;
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continue;
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}
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} else {
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if (quoteStart === false) {
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if (c === '<') {
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rethtml += noTag(html.slice(lastPos, currentPos));
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tagStart = currentPos;
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lastPos = currentPos;
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continue;
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}
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if (c === '>') {
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addNewTag(html.slice(tagStart, currentPos + 1), currentPos);
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tagStart = false;
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continue;
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}
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if (c === '"' || c === "'") {
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quoteStart = c;
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continue;
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}
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} else {
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if (c === quoteStart) {
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quoteStart = false;
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continue;
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}
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}
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}
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}
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if (lastPos < html.length) {
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rethtml += noTag(html.substr(lastPos));
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}
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return rethtml;
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};
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// 默认配置
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exports.whiteList = defaultWhiteList;
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exports.onTagAttr = defaultOnTagAttr;
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exports.onIgnoreTag = defaultOnIgnoreTag;
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// 工具函数
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exports.utils = require('./utils');
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