解决 IE6 li:hover兼容性

 ie6是css1.0，不支持非a的hover伪类，若想实现hover效果需要写js或者是把li变成a来使用，以下解决方法是用的JS。

/*解决ie6.0 的hover兼容问题*/

新建.htc文件，内容如下：

<attach event="ondocumentready" handler="parseStylesheets" />
<script>
var csshoverReg = /(^|\s)(([^a]([^ ]+)?)|(a([^#.][^ ]+)+)):(hover|active)/i,
currentSheet, doc = window.document, hoverEvents = [], activators = {
onhover:{on:'onmouseover', off:'onmouseout'},
onactive:{on:'onmousedown', off:'onmouseup'}
}
function parseStylesheets() {
if(!/MSIE (5|6)/.test(navigator.userAgent)) return;
window.attachEvent('onunload', unhookHoverEvents);
var sheets = doc.styleSheets, l = sheets.length;
for(var i=0; i<l; i++)
parseStylesheet(sheets[i]);
}
function parseStylesheet(sheet) {
if(sheet.imports) {
try {
var imports = sheet.imports, l = imports.length;
for(var i=0; i<l; i++) parseStylesheet(sheet.imports[i]);
} catch(securityException){}
}
try {
var rules = (currentSheet = sheet).rules, l = rules.length;
for(var j=0; j<l; j++) parseCSSRule(rules[j]);
} catch(securityException){}
}
function parseCSSRule(rule) {
var select = rule.selectorText, style = rule.style.cssText;
if(!csshoverReg.test(select) || !style) return;
var pseudo = select.replace(/[^:]+:([a-z-]+).*/i, 'on$1');
var newSelect = select.replace(/(\.([a-z0-9_-]+):[a-z]+)|(:[a-z]+)/gi, '.$2' + pseudo);
var className = (/\.([a-z0-9_-]*on(hover|active))/i).exec(newSelect)[1];
var affected = select.replace(/:(hover|active).*$/, '');
var elements = getElementsBySelect(affected);
if(elements.length == 0) return;
currentSheet.addRule(newSelect, style);
for(var i=0; i<elements.length; i++)
new HoverElement(elements[i], className, activators[pseudo]);
}
function HoverElement(node, className, events) {
if(!node.hovers) node.hovers = {};
if(node.hovers[className]) return;
node.hovers[className] = true;
hookHoverEvent(node, events.on, function() { node.className += ' ' + className; });
hookHoverEvent(node, events.off, function() { node.className = node.className.replace(new RegExp('\\s+'+className, 'g'),''); });
}
function hookHoverEvent(node, type, handler) {
node.attachEvent(type, handler);
hoverEvents[hoverEvents.length] = {
node:node, type:type, handler:handler
};
}
function unhookHoverEvents() {
for(var e,i=0; i<hoverEvents.length; i++) {
e = hoverEvents[i];
e.node.detachEvent(e.type, e.handler);
}
}
function getElementsBySelect(rule) {
var parts, nodes = [doc];
parts = rule.split(' ');
for(var i=0; i<parts.length; i++) {
nodes = getSelectedNodes(parts[i], nodes);
} return nodes;
}
function getSelectedNodes(select, elements) {
var result, node, nodes = [];
var identify = (/\#([a-z0-9_-]+)/i).exec(select);
if(identify) {
var element = doc.getElementById(identify[1]);
return element? [element]:nodes;
}

var classname = (/\.([a-z0-9_-]+)/i).exec(select);
var tagName = select.replace(/(\.|\#|\:)[a-z0-9_-]+/i, '');
var classReg = classname? new RegExp('\\b' + classname[1] + '\\b'):false;
for(var i=0; i<elements.length; i++) {
result = tagName? elements[i].all.tags(tagName):elements[i].all;
for(var j=0; j<result.length; j++) {
node = result[j];
if(classReg && !classReg.test(node.className)) continue;
nodes[nodes.length] = node;
}
}

return nodes;
}
</script>


页面中引用htc文件：

<style>
<!--
body
{
/*
首先不支持绝对路径，只支持相对路径。
其次，是相对于当前ASPX网页的相对路径，和CSS文件的位置无关。 （这句话是什么意思我没懂，不过写上供懂的朋友研究。）*/ 
behavior: url(hover.htc) /*可在IE6,7中对非<a>元素使用hover等伪类(路径要写对哦~要不然没效果的。)*/ 
}
-->
</style>

这样，在IE6中li:hover就好用了，这个方法我试过了，所以才写出来的。