Accordion Menu

<script type="text/javascript">
           ddaccordion.init({
        headerclass: "headerbar", //Shared CSS class name of headers group
        contentclass: "submenu", //Shared CSS class name of contents group
        revealtype: "click", //Reveal content when user clicks or onmouseover the header? Valid value: "click", "clickgo", or "mouseover"
        mouseoverdelay: 200, //if revealtype="mouseover", set delay in milliseconds before header expands onMouseover
        collapseprev: true, //Collapse previous content (so only one open at any time)? true/false
        defaultexpanded: [], //index of content(s) open by default [index1, index2, etc] [] denotes no content
        onemustopen: false, //Specify whether at least one header should be open always (so never all headers closed)
        animatedefault: false, //Should contents open by default be animated into view?
        persiststate: true, //persist state of opened contents within browser session?
        toggleclass: ["", "selected"], //Two CSS classes to be applied to the header when it's collapsed and expanded, respectively ["class1", "class2"]
        togglehtml: ["", "", ""], //Additional HTML added to the header when it's collapsed and expanded, respectively  ["position", "html1", "html2"] (see docs)
        animatespeed: "slow", //speed of animation: integer in milliseconds (ie: 200), or keywords "fast", "normal", or "slow"
        oninit:function(headers, expandedindices){ //custom code to run when headers have initalized
            //do nothing
        },
        onopenclose:function(header, index, state, isuseractivated){ //custom code to run whenever a header is opened or closed
            //do nothing
        }
    })
    
    </script>

var ddaccordion={
    ajaxloadingmsg: '<img src="loading2.gif" /><br />Loading Content...', //customize HTML to output while Ajax content is being fetched (if applicable)

    headergroup: {}, //object to store corresponding header group based on headerclass value
    contentgroup: {}, //object to store corresponding content group based on headerclass value

    preloadimages:function($images){
        $images.each(function(){
            var preloadimage=new Image()
            preloadimage.src=this.src
        })
    },

    expandone:function(headerclass, selected){ //PUBLIC function to expand a particular header
        this.toggleone(headerclass, selected, "expand")
    },

    collapseone:function(headerclass, selected){ //PUBLIC function to collapse a particular header
        this.toggleone(headerclass, selected, "collapse")
    },

    expandall:function(headerclass){ //PUBLIC function to expand all headers based on their shared CSS classname
        var $headers=this.headergroup[headerclass]
        this.contentgroup[headerclass].filter(':hidden').each(function(){
            $headers.eq(parseInt($(this).attr('contentindex'))).trigger("evt_accordion")
        })
    },

    collapseall:function(headerclass){ //PUBLIC function to collapse all headers based on their shared CSS classname
        var $headers=this.headergroup[headerclass]
        this.contentgroup[headerclass].filter(':visible').each(function(){
            $headers.eq(parseInt($(this).attr('contentindex'))).trigger("evt_accordion")
        })
    },

    toggleone:function(headerclass, selected, optstate){ //PUBLIC function to expand/ collapse a particular header
        var $targetHeader=this.headergroup[headerclass].eq(selected)
        var $subcontent=this.contentgroup[headerclass].eq(selected)
        if (typeof optstate=="undefined" || optstate=="expand" && $subcontent.is(":hidden") || optstate=="collapse" && $subcontent.is(":visible"))
            $targetHeader.trigger("evt_accordion")
    },

    ajaxloadcontent:function($targetHeader, $targetContent, config, callback){
        var ajaxinfo=$targetHeader.data('ajaxinfo')

        function handlecontent(content){ //nested function
            if (content){ //if ajax content has loaded
                ajaxinfo.cacheddata=content //remember ajax content
                ajaxinfo.status="cached" //set ajax status to cached
                if ($targetContent.queue("fx").length==0){ //if this content isn't currently expanding or collapsing
                    $targetContent.hide().html(content) //hide loading message, then set sub content's HTML to ajax content
                    ajaxinfo.status="complete" //set ajax status to complete
                    callback() //execute callback function- expand this sub content
                }
            }
            if (ajaxinfo.status!="complete"){
                setTimeout(function(){handlecontent(ajaxinfo.cacheddata)}, 100) //call handlecontent() again until ajax content has loaded (ajaxinfo.cacheddata contains data)
            }
        } //end nested function

        if (ajaxinfo.status=="none"){ //ajax data hasn't been fetched yet
            $targetContent.html(this.ajaxloadingmsg)
            $targetContent.slideDown(config.animatespeed)
            ajaxinfo.status="loading" //set ajax status to "loading"
            $.ajax({
                url: ajaxinfo.url, //path to external menu file
                error:function(ajaxrequest){
                    handlecontent('Error fetching content. Server Response: '+ajaxrequest.responseText)
                },
                success:function(content){
                    content=(content=="")? " " : content //if returned content is empty, set it to "space" is content no longer returns false/empty (hasn't loaded yet)
                    handlecontent(content)
                }
            })
        }
        else if (ajaxinfo.status=="loading")
            handlecontent(ajaxinfo.cacheddata)
    },

    expandit:function($targetHeader, $targetContent, config, useractivated, directclick, skipanimation){
        var ajaxinfo=$targetHeader.data('ajaxinfo')
        if (ajaxinfo){ //if this content should be fetched via Ajax
            if (ajaxinfo.status=="none" || ajaxinfo.status=="loading")
                this.ajaxloadcontent($targetHeader, $targetContent, config, function(){ddaccordion.expandit($targetHeader, $targetContent, config, useractivated, directclick)})
            else if (ajaxinfo.status=="cached"){
                $targetContent.html(ajaxinfo.cacheddata)
                ajaxinfo.cacheddata=null
                ajaxinfo.status="complete"
            }
        }
        this.transformHeader($targetHeader, config, "expand")
        $targetContent.slideDown(skipanimation? 0 : config.animatespeed, function(){
            config.onopenclose($targetHeader.get(0), parseInt($targetHeader.attr('headerindex')), $targetContent.css('display'), useractivated)
            if (config.postreveal=="gotourl" && directclick){ //if revealtype is "Go to Header URL upon click", and this is a direct click on the header
                var targetLink=($targetHeader.is("a"))? $targetHeader.get(0) : $targetHeader.find('a:eq(0)').get(0)
                if (targetLink) //if this header is a link
                    setTimeout(function(){location=targetLink.href}, 200) //ignore link target, as window.open(targetLink, targetLink.target) doesn't work in FF if popup blocker enabled
            }
        })
    },

    collapseit:function($targetHeader, $targetContent, config, isuseractivated){
        this.transformHeader($targetHeader, config, "collapse")
        $targetContent.slideUp(config.animatespeed, function(){config.onopenclose($targetHeader.get(0), parseInt($targetHeader.attr('headerindex')), $targetContent.css('display'), isuseractivated)})
    },

    transformHeader:function($targetHeader, config, state){
        $targetHeader.addClass((state=="expand")? config.cssclass.expand : config.cssclass.collapse) //alternate btw "expand" and "collapse" CSS classes
        .removeClass((state=="expand")? config.cssclass.collapse : config.cssclass.expand)
        if (config.htmlsetting.location=='src'){ //Change header image (assuming header is an image)?
            $targetHeader=($targetHeader.is("img"))? $targetHeader : $targetHeader.find('img').eq(0) //Set target to either header itself, or first image within header
            $targetHeader.attr('src', (state=="expand")? config.htmlsetting.expand : config.htmlsetting.collapse) //change header image
        }
        else if (config.htmlsetting.location=="prefix") //if change "prefix" HTML, locate dynamically added ".accordprefix" span tag and change it
            $targetHeader.find('.accordprefix').html((state=="expand")? config.htmlsetting.expand : config.htmlsetting.collapse)
        else if (config.htmlsetting.location=="suffix")
            $targetHeader.find('.accordsuffix').html((state=="expand")? config.htmlsetting.expand : config.htmlsetting.collapse)
    },

    urlparamselect:function(headerclass){
        var result=window.location.search.match(new RegExp(headerclass+"=((\\d+)(,(\\d+))*)", "i")) //check for "?headerclass=2,3,4" in URL
        if (result!=null)
            result=RegExp.$1.split(',')
        return result //returns null, [index], or [index1,index2,etc], where index are the desired selected header indices
    },

    getCookie:function(Name){
        var re=new RegExp(Name+"=[^;]+", "i") //construct RE to search for target name/value pair
        if (document.cookie.match(re)) //if cookie found
            return document.cookie.match(re)[0].split("=")[1] //return its value
        return null
    },

    setCookie:function(name, value){
        document.cookie = name + "=" + value + "; path=/"
    },

    init:function(config){
    document.write('<style type="text/css">\n')
    document.write('.'+config.contentclass+'{display: none}\n') //generate CSS to hide contents
    document.write('a.hiddenajaxlink{display: none}\n') //CSS class to hide ajax link
    document.write('<\/style>')
    jQuery(document).ready(function($){
        ddaccordion.urlparamselect(config.headerclass)
        var persistedheaders=ddaccordion.getCookie(config.headerclass)
        ddaccordion.headergroup[config.headerclass]=$('.'+config.headerclass) //remember header group for this accordion
        ddaccordion.contentgroup[config.headerclass]=$('.'+config.contentclass) //remember content group for this accordion
        var $headers=ddaccordion.headergroup[config.headerclass]
        var $subcontents=ddaccordion.contentgroup[config.headerclass]
        config.cssclass={collapse: config.toggleclass[0], expand: config.toggleclass[1]} //store expand and contract CSS classes as object properties
        config.revealtype=config.revealtype || "click"
        config.revealtype=config.revealtype.replace(/mouseover/i, "mouseenter")
        if (config.revealtype=="clickgo"){
            config.postreveal="gotourl" //remember added action
            config.revealtype="click" //overwrite revealtype to "click" keyword
        }
        if (typeof config.togglehtml=="undefined")
            config.htmlsetting={location: "none"}
        else
            config.htmlsetting={location: config.togglehtml[0], collapse: config.togglehtml[1], expand: config.togglehtml[2]} //store HTML settings as object properties
        config.oninit=(typeof config.oninit=="undefined")? function(){} : config.oninit //attach custom "oninit" event handler
        config.onopenclose=(typeof config.onopenclose=="undefined")? function(){} : config.onopenclose //attach custom "onopenclose" event handler
        var lastexpanded={} //object to hold reference to last expanded header and content (jquery objects)
        var expandedindices=ddaccordion.urlparamselect(config.headerclass) || ((config.persiststate && persistedheaders!=null)? persistedheaders : config.defaultexpanded)
        if (typeof expandedindices=='string') //test for string value (exception is config.defaultexpanded, which is an array)
            expandedindices=expandedindices.replace(/c/ig, '').split(',') //transform string value to an array (ie: "c1,c2,c3" becomes [1,2,3]
        if (expandedindices.length==1 && expandedindices[0]=="-1") //check for expandedindices value of [-1], indicating persistence is on and no content expanded
            expandedindices=[]
        if (config["collapseprev"] && expandedindices.length>1) //only allow one content open?
            expandedindices=[expandedindices.pop()] //return last array element as an array (for sake of jQuery.inArray())
        if (config["onemustopen"] && expandedindices.length==0) //if at least one content should be open at all times and none are, open 1st header
            expandedindices=[0]
        $headers.each(function(index){ //loop through all headers
            var $header=$(this)
            if (/(prefix)|(suffix)/i.test(config.htmlsetting.location) && $header.html()!=""){ //add a SPAN element to header depending on user setting and if header is a container tag
                $('<span class="accordprefix"></span>').prependTo(this)
                $('<span class="accordsuffix"></span>').appendTo(this)
            }
            $header.attr('headerindex', index+'h') //store position of this header relative to its peers
            $subcontents.eq(index).attr('contentindex', index+'c') //store position of this content relative to its peers
            var $subcontent=$subcontents.eq(index)
            var $hiddenajaxlink=$subcontent.find('a.hiddenajaxlink:eq(0)') //see if this content should be loaded via ajax
            if ($hiddenajaxlink.length==1){
                $header.data('ajaxinfo', {url:$hiddenajaxlink.attr('href'), cacheddata:null, status:'none'}) //store info about this ajax content inside header
            }
            var needle=(typeof expandedindices[0]=="number")? index : index+'' //check for data type within expandedindices array- index should match that type
            if (jQuery.inArray(needle, expandedindices)!=-1){ //check for headers that should be expanded automatically (convert index to string first)
                ddaccordion.expandit($header, $subcontent, config, false, false, !config.animatedefault) //3rd last param sets 'isuseractivated' parameter, 2nd last sets isdirectclick, last sets skipanimation param
                lastexpanded={$header:$header, $content:$subcontent}
            }  //end check
            else{
                $subcontent.hide()
                config.onopenclose($header.get(0), parseInt($header.attr('headerindex')), $subcontent.css('display'), false) //Last Boolean value sets 'isuseractivated' parameter
                ddaccordion.transformHeader($header, config, "collapse")
            }
        })
        $headers.bind("evt_accordion", function(e, isdirectclick){ //assign CUSTOM event handler that expands/ contacts a header
                var $subcontent=$subcontents.eq(parseInt($(this).attr('headerindex'))) //get subcontent that should be expanded/collapsed
                if ($subcontent.css('display')=="none"){
                    ddaccordion.expandit($(this), $subcontent, config, true, isdirectclick) //2nd last param sets 'isuseractivated' parameter
                    if (config["collapseprev"] && lastexpanded.$header && $(this).get(0)!=lastexpanded.$header.get(0)){ //collapse previous content?
                        ddaccordion.collapseit(lastexpanded.$header, lastexpanded.$content, config, true) //Last Boolean value sets 'isuseractivated' parameter
                    }
                    lastexpanded={$header:$(this), $content:$subcontent}
                }
                else if (!config["onemustopen"] || config["onemustopen"] && lastexpanded.$header && $(this).get(0)!=lastexpanded.$header.get(0)){
                    ddaccordion.collapseit($(this), $subcontent, config, true) //Last Boolean value sets 'isuseractivated' parameter
                }
         })
        $headers.bind(config.revealtype, function(){
            if (config.revealtype=="mouseenter"){
                clearTimeout(config.revealdelay)
                var headerindex=parseInt($(this).attr("headerindex"))
                config.revealdelay=setTimeout(function(){ddaccordion.expandone(config["headerclass"], headerindex)}, config.mouseoverdelay || 0)
            }
            else{
                $(this).trigger("evt_accordion", [true]) //last parameter indicates this is a direct click on the header
                return false //cancel default click behavior
            }
        })
        $headers.bind("mouseleave", function(){
            clearTimeout(config.revealdelay)
        })
        config.oninit($headers.get(), expandedindices)
        $(window).bind('unload', function(){ //clean up and persist on page unload
            $headers.unbind()
            var expandedindices=[]
            $subcontents.filter(':visible').each(function(index){ //get indices of expanded headers
                expandedindices.push($(this).attr('contentindex'))
            })
            if (config.persiststate==true && $headers.length>0){ //persist state?
                expandedindices=(expandedindices.length==0)? '-1c' : expandedindices //No contents expanded, indicate that with dummy '-1c' value?
                ddaccordion.setCookie(config.headerclass, expandedindices)
            }
        })
    })
    }
}

//preload any images defined inside ajaxloadingmsg variable
ddaccordion.preloadimages(jQuery(ddaccordion.ajaxloadingmsg).filter('img'))

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<ul class="submenu">

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</ul>        

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