source: downloads/boost_1_33_1/more/css_0/csshover.htc @ 13

<attach event="ondocumentready" handler="parseStylesheets" />
<script language="JScript">
/**
 *  Pseudos - V1.30.050121 - hover & active
 *  ---------------------------------------------
 *  Peterned - http://www.xs4all.nl/~peterned/
 *  (c) 2005 - Peter Nederlof
 *
 *  Credits  - Arnoud Berendsen 
 *           - Martin Reurings
 *           - Robert Hanson
 *
 *  howto: body { behavior:url("csshover.htc"); }
 *  ---------------------------------------------
 */

var currentSheet, doc = window.document, activators = {
    onhover:{on:'onmouseover', off:'onmouseout'},
    onactive:{on:'onmousedown', off:'onmouseup'}
}

function parseStylesheets() {
    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(!(/(^|\s)(([^a]([^ ]+)?)|(a([^#.][^ ]+)+)):(hover|active)/i).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, '.$2' + pseudo);
        var className = (/\.([a-z0-9_-]*on(hover|active))/i).exec(newSelect)[1];
        var affected = select.replace(/:hover.*$/, '');
        var elements = getElementsBySelect(affected);

        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;
    node.attachEvent(events.on,
        function() { node.className += ' ' + className; });
    node.attachEvent(events.off,
        function() { node.className = 
            node.className.replace(new RegExp('\\s+'+className, 'g'),''); });
}

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 classname = (/\.([a-z0-9_-]+)/i).exec(select);
        var identify = (/\#([a-z0-9_-]+)/i).exec(select);
        var tagName = select.replace(/(\.|\#|\:)[a-z0-9_-]+/i, '');
        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((identify && node.id != identify[1]) || (classname && !(new RegExp('\\b' +
                    classname[1] + '\\b').exec(node.className)))) continue;
                nodes[nodes.length] = node;
            }
        }
        return nodes;
    }
</script>