ÿþ// CSS helper functions

CSS = {

    // Adds a class to an element.

    AddClass: function (e, c) {

        if (!e.className.match(new RegExp("\\b" + c + "\\b", "i")))

            e.className += (e.className ? " " : "") + c;

    },



    // Removes a class from an element.

    RemoveClass: function (e, c) {

        e.className = e.className.replace(new RegExp(" \\b" + c + "\\b|\\b" + c + "\\b ?", "gi"), "");

    }

};



// Functions for handling tabs.

Tabs = {

    // Changes to the tab with the specified ID.

    GoTo: function (contentId, skipReplace) {

        // This variable will be true if a tab for the specified

        // content ID was found.

        var foundTab = false;



        // Get the TOC element.

        var toc = document.getElementById("toc");

        if (toc) {

            var lis = toc.getElementsByTagName("li");

            for (var j = 0; j < lis.length; j++) {

                var li = lis[j];



                // Give the current tab link the class "current" and

                // remove the class from any other TOC links.

                var anchors = li.getElementsByTagName("a");

                for (var k = 0; k < anchors.length; k++) {

                    if (anchors[k].hash == "#" + contentId) {

                        CSS.AddClass(li, "current");

                        foundTab = true;

                        break;

                    } else {

                        CSS.RemoveClass(li, "current");

                    }

                }

            }

        }



        // Show the content with the specified ID.

        var divsToHide = [];

        var divs = document.getElementsByTagName("div");

        for (var i = 0; i < divs.length; i++) {

            var div = divs[i];



            if (div.className.match(/\bcontent\b/i)) {

                if (div.id == "_" + contentId)

                    div.style.display = "block";

                else

                    divsToHide.push(div);

            }

        }



        // Hide the other content boxes.

        for (var i = 0; i < divsToHide.length; i++)

            divsToHide[i].style.display = "none";



        // Change the address bar.

        if (!skipReplace) window.location.replace("#" + contentId);

    },



    OnClickHandler: function (e) {

        // Stop the event (to stop it from scrolling or

        // making an entry in the history).

        if (!e) e = window.event;

        if (e.preventDefault) e.preventDefault(); else e.returnValue = false;



        // Get the name of the anchor of the link that was clicked.

        Tabs.GoTo(this.hash.substring(1));

    },



    Init: function () {

        if (!document.getElementsByTagName) return;



        // Attach an onclick event to all the anchor links on the page.

        var anchors = document.getElementsByTagName("a");

        for (var i = 0; i < anchors.length; i++) {

            var a = anchors[i];

            if (a.hash) a.onclick = Tabs.OnClickHandler;

        }



        var contentId;

        if (window.location.hash) contentId = window.location.hash.substring(1);



        var divs = document.getElementsByTagName("div");

        for (var i = 0; i < divs.length; i++) {

            var div = divs[i];



            if (div.className.match(/\bcontent\b/i)) {

                if (!contentId) contentId = div.id;

                div.id = "_" + div.id;

            }

        }



        if (contentId) Tabs.GoTo(contentId, true);

    }

};



// Hook up the OnLoad event to the tab initialization function.

window.onload = Tabs.Init;



// Hide the content while waiting for the onload event to trigger.

var contentId = window.location.hash || "#Introduction";



if (document.createStyleSheet) {

    var style = document.createStyleSheet();

    style.addRule("div.content", "display: none;");

    style.addRule("div" + contentId, "display: block;");

} else {

    var head = document.getElementsByTagName("head")[0];

    if (head) {

        var style = document.createElement("style");

        style.setAttribute("type", "text/css");

        style.appendChild(document.createTextNode("div.content { display: none; }"));

		style.appendChild(document.createTextNode("div" + contentId + " { display: block; }"));

        head.appendChild(style);

    }

}