Chip 2003 January/01_03.iso/software/snahit/files/NAV/SWPlugin.dll/HTML/RESOURCE.JS

JavaScript | 2002-11-05 | 12.2 KB | 368 lines

// resource.js
//
// Initial Author:  Alex Hui
// Date:  May 10, 2000
//
// Purpose:
// --------
// This file contains the functions to access the resources,
// such as the string tables and image tables, which are stored
// in a resource.xml.  The document is in XML format, but the
// users of the library of functions provided here should not
// need to know that detail.
//
// To use this "library", if we may call it so, add this line
// to the HTML file:
//   <SCRIPT LANGUAGE="JavaScript" SRC="resource.js"></SCRIPT>

// Note:
// -----
// The support for XML under IE4 and IE5 are quite different.
// IE5 provides a rich set of methods such as searching for
// certain nodes given a tag name or certain attribute values.
// On the other hand, basically IE4 only provides methods to
// traverse the XML document tree and retrieve data.
//
// In fact, the XML object in the two versions are distinct.
// In IE4, many things have to be done ourselves.  With some
// minor adjustments code written for IE4 will also work in
// IE5.  However, for the following 4 reasons there will be
// separate implementations for IE4 and IE5+:
// 1) robustness, 2) efficiency, 3) in case future versions of
// IE will drop support for the old XML object and 4) for the
// sake of not using legacy code if we ever drop support for IE4.

// "Exports":
// ----------
// function LoadResourceDoc()
// function GetString(StringID, Section, Language)
// function GetImage(ImageID, Section)
// (other functions in this file are supposed to be internal)

var DefaultLanguage;            // language to use when not specified
var DefaultImageTableSection;   // image table section to use when not specified
var IE4ResourceDoc;             // the XML object in IE4
var IE5ResourceDoc;             // the XML object in IE5 or higher

// IE Version Detection ***********************************
function IEVersion()
{
    var ua = window.navigator.userAgent
    var msie = ua.indexOf("MSIE ")

    // If Internet Explorer, return version number
    // If another browser, return 0
    if (msie > 0)
        return parseInt( ua.substring(msie+5, ua.indexOf(".", msie)) );
    else
        return 0;
}

// IE4 Functions ******************************************
function GetXMLDocURL()
{
    var CurrentURL;         // HREF of the viewed document
    var XMLDocURL;          // built from CurrentURL but with the XML document as the filename
    var FilenameIndex;      // position of the filename (no path) within CurrentURL

    // note: the filename is always preceded by "/" no matter what protocol
    CurrentURL = window.location.href;
    FilenameIndex = CurrentURL.lastIndexOf("/") + 1;
    XMLDocURL = CurrentURL.substring(0, FilenameIndex) + "resource.xml";
    return XMLDocURL;
}

function IE4LoadResourceDoc()
{
    IE4ResourceDoc = new ActiveXObject("msxml");
    // Docs say async should be false so that the whole file
    // is loaded before returning, but we get the error
    // "no data available in requested resource" whenever we
    // use the dll resources.
    // Setting it to true seems to work fine. (?!)
    IE4ResourceDoc.async = true;
    IE4ResourceDoc.url = GetXMLDocURL();            // in IE4 we must specify a protocol
    var bLoaded = (IE4ResourceDoc.root != null);
    if (bLoaded)
    {
        DefaultLanguage = IE4ResourceDoc.root.getAttribute("DEFAULT_LANGUAGE");
        DefaultImageTableSection = IE4ResourceDoc.root.getAttribute("DEFAULT_IMAGETABLE_SECTION");
    }

    return bLoaded;
}

// returns a <STRINGTABLE> xml element or null
function IE4FindStringTable(Section, Language)
{
    // enumerate immediate children of the Resources root
    var Level1Nodes = IE4ResourceDoc.root.children;     // root is level 0
    var CurrentNode;
    var NodeLanguage;
    var NodeSection;
    var bIsElement
    var n;
    for (n = 0; n < Level1Nodes.length; n++)
    {
        CurrentNode = Level1Nodes.item(n);
        bIsElement = (CurrentNode.type == 0);

        // check if the CurrentNode refers to a STRINGTABLE element
        // (note: second expression must not execute if not an element)
        if (bIsElement && CurrentNode.tagName == "STRINGTABLE")
        {
            NodeLanguage = CurrentNode.getAttribute("LANGUAGE");
            NodeSection = CurrentNode.getAttribute("SECTION");
            if (NodeSection == Section && NodeLanguage == Language)
                return CurrentNode;     // found!
        }
    }   // for each level 1 nodes

    // all level 1 nodes exhausted
    return null;
}

// returns a <STRING> xml element or null
function IE4FindString(StringID, StringTable)
{
    // only <STRING> elements and comments are inside a string table
    var Nodes = StringTable.children;
    var CurrentNode;
    var NodeID;
    var n;

    if (Nodes != null)
    {
        for (n = 0; n < Nodes.length; n++)
        {
            CurrentNode = Nodes.item(n);
            NodeID = CurrentNode.getAttribute("ID");
            if (NodeID == StringID)
                return CurrentNode;         // found!
        }
    }

    // string table child nodes exhausted
    return null;
}

// returns the retrieved string or or null
// see IE5GetString() for additional information
function IE4GetString(StringID, Section, Language)
{
    var bLanguageNotSpecified = (Language == "");
    var StringTableSection;
    var StringElement;

    if (Section == "") Section = "default"
    if (Language == "") Language = DefaultLanguage;

    // Get the string table with the matching language and section
    StringTableSection = IE4FindStringTable(Section, Language);
    if (StringTableSection == null)
        return null;

    StringElement = IE4FindString(StringID, StringTableSection);
    if (StringElement == null && bLanguageNotSpecified)
    {
        // since no language was specified, we first tried the DefaultLanguage,
        // we can't find it so now we try the neutral language
        return IE4GetString(StringID, Section, "Neutral");
    }
    else if (StringElement == null)
        return null;
    else
        return StringElement.text;
}

// Each of the following image functions are similar to a
// corresponding string function, but I have provided two
// sets of functions.  This is to anticipate that the two
// types of tables might develop into entirely different
// formats.  Also, code is easier to read this way (though
// we may sacrifice some maintainability).
// I state my reasoning here to provide a basis for evaluation
// when changes are being considered.

// returns a <IMAGETABLE> xml element or null
function IE4FindImageTable(Section)
{
    // enumerate immediate children of the Resources root
    var Level1Nodes = IE4ResourceDoc.root.children;     // root is level 0
    var CurrentNode;
    var NodeSection;
    var bIsElement
    var n;
    for (n = 0; n < Level1Nodes.length; n++)
    {
        CurrentNode = Level1Nodes.item(n);
        bIsElement = (CurrentNode.type == 0);

        // check if the CurrentNode refers to a IMAGETABLE element
        // (note: second expression must not execute if not an element)
        if (bIsElement && CurrentNode.tagName == "IMAGETABLE")
        {
            NodeSection = CurrentNode.getAttribute("SECTION");
            if (NodeSection == Section)
                return CurrentNode;     // found!
        }
    }   // for each level 1 nodes

    // all level 1 nodes exhausted
    return null;
}

// returns an <IMAGE> xml element or null
function IE4FindImage(ImageID, ImageTable)
{
    // only <IMAGE> elements and comments are inside a image table
    var Nodes = ImageTable.children;
    var CurrentNode;
    var NodeID;
    var n;
    for (n = 0; n < Nodes.length; n++)
    {
        CurrentNode = Nodes.item(n);
        NodeID = CurrentNode.getAttribute("ID");
        if (NodeID == ImageID)
            return CurrentNode;         // found!
    }

    // image table child nodes exhausted
    return null;
}

// returns the image's filename or null
// See IE5GetImage() for more details
function IE4GetImage(ImageID, Section)
{
    var ImageTableSection;
    var ImageElement;

    if (Section == "")
        Section = DefaultImageTableSection;

    // Get the image table with the matching section
    ImageTableSection = IE4FindImageTable(Section);
    if (ImageTableSection == null)
        return null;

    ImageElement = IE4FindImage(ImageID, ImageTableSection);
    if (ImageElement == null)
        return null;
    else
        return ImageElement.text;
}

// IE5+ Functions *****************************************
function IE5LoadResourceDoc()
{
    IE5ResourceDoc = new ActiveXObject("Microsoft.XMLDOM");
    // Docs say async should be false so that the whole file
    // is loaded before returning, but we get the error
    // "no data available in requested resource" whenever
    // we get the file from the dll resources.
    // Setting it to true seems to work fine. (?!)
    IE5ResourceDoc.async = true;
    var bLoaded;
    bLoaded = IE5ResourceDoc.load("resource.xml");
    if (bLoaded)
    {
        DefaultLanguage = IE5ResourceDoc.documentElement.getAttribute("DEFAULT_LANGUAGE");
        DefaultImageTableSection = IE5ResourceDoc.documentElement.getAttribute("DEFAULT_IMAGETABLE_SECTION");
    }

    return bLoaded;
}

// uses global variable IE5ResourceDoc as the loaded resource document
// uses global variable DefaultLanguage when no Language is specified
// returns string, or null if not found
// concept: if you specify it, we assume that's what you want..
//          if you don't specify it, we'll search default places for you
function IE5GetString(StringID, Section, Language)
{
    var bLanguageNotSpecified = (Language == "");
    var StringTableSection;
    var StringElement;

    if (Section == "") Section = "default";
    if (Language == "") Language = DefaultLanguage;

    // Get the string table with the matching language and section
    StringTableSection = IE5ResourceDoc.documentElement.selectSingleNode(
        "./STRINGTABLE"
        + "[@LANGUAGE='" + Language + "']"
        + "[@SECTION='" + Section + "']"
    );
    if (StringTableSection == null)
        return null;

    StringElement = StringTableSection.selectSingleNode(
        "./STRING"
        + "[@ID='" + StringID + "']"
    );
    if (StringElement == null && bLanguageNotSpecified)
        // since no language was specified, we first tried the DefaultLanguage,
        // we can't find it so now try the neutral language
        return IE5GetString(StringID, Section, "Neutral");
    else if (StringElement == null)
        return null;
    else
        return StringElement.text;
}

// returns the image's filename or null
// Parameters: ImageID is always needed, but if no Section is specified
//             then the default section is assumed
function IE5GetImage(ImageID, Section)
{
    var ImageTableSection;
    var ImageElement;

    if (Section == "")
        Section = DefaultImageTableSection;

    // Get the image table with the matching section
    ImageTableSection = IE5ResourceDoc.documentElement.selectSingleNode(
        "./IMAGETABLE"
        + "[@SECTION='" + Section + "']"
    );
    if (ImageTableSection == null)
        return null;

    ImageElement = ImageTableSection.selectSingleNode(
        "./IMAGE"
        + "[@ID='" + ImageID + "']"
    );
    if (ImageElement == null)
        return null;
    else
        return ImageElement.text;
}

// Generic Functions **************************************
function LoadResourceDoc()
{
    if (IEVersion() >= 5)
        return IE5LoadResourceDoc();
    else
        return IE4LoadResourceDoc();
}

function GetString(StringID, Section, Language)
{
    if (IEVersion() >= 5)
        return IE5GetString(StringID, Section, Language);
    else
        return IE4GetString(StringID, Section, Language);
}

function GetImage(ImageID, Section)
{
    if (IEVersion() >= 5)
        return IE5GetImage(ImageID, Section);
    else
        return IE4GetImage(ImageID, Section);
}