// ===================================================================
// Author: Matt Kruse <matt@mattkruse.com>
// WWW: http://www.mattkruse.com/
//
// NOTICE: You may use this code for any purpose, commercial or
// private, without any further permission from the author. You may
// remove this notice from your final code if you wish, however it is
// appreciated by the author if at least my web site address is kept.
//
// You may *NOT* re-distribute this code in any way except through its
// use. That means, you can include it in your product, or your web
// site, or any other form where the code is actually being used. You
// may not put the plain javascript up on your site for download or
// include it in your javascript libraries for download. 
// If you wish to share this code with others, please just point them
// to the URL instead.
// Please DO NOT link directly to my .js files from your site. Copy
// the files to your server and use them there. Thank you.
// ===================================================================

/* 
AnchorPosition.js
Author: Matt Kruse
Last modified: 10/11/02

DESCRIPTION: These functions find the position of an <A> tag in a document,
so other elements can be positioned relative to it.

COMPATABILITY: Netscape 4.x,6.x,Mozilla, IE 5.x,6.x on Windows. Some small
positioning errors - usually with Window positioning - occur on the 
Macintosh platform.

FUNCTIONS:
getAnchorPosition(anchorname)
Returns an Object() having .x and .y properties of the pixel coordinates
of the upper-left corner of the anchor. Position is relative to the PAGE.

getAnchorWindowPosition(anchorname)
Returns an Object() having .x and .y properties of the pixel coordinates
of the upper-left corner of the anchor, relative to the WHOLE SCREEN.

NOTES:

1) For popping up separate browser windows, use getAnchorWindowPosition. 
Otherwise, use getAnchorPosition

2) Your anchor tag MUST contain both NAME and ID attributes which are the 
same. For example:
<A NAME="test" ID="test"> </A>

3) There must be at least a space between <A> </A> for IE5.5 to see the 
anchor tag correctly. Do not do <A></A> with no space.
*/

// getAnchorPosition(anchorname)
//   This function returns an object having .x and .y properties which are the coordinates
//   of the named anchor, relative to the page.
function getAnchorPosition(anchorname) {
    // This function will return an Object with x and y properties
    var useWindow = false;
    var coordinates = new Object();
    var x = 0, y = 0;
    // Browser capability sniffing
    var use_gebi = false, use_css = false, use_layers = false;
    if (document.getElementById) { use_gebi = true; }
    else if (document.all) { use_css = true; }
    else if (document.layers) { use_layers = true; }
    // Logic to find position
    if (use_gebi && document.all) {
        x = AnchorPosition_getPageOffsetLeft(document.all[anchorname]);
        y = AnchorPosition_getPageOffsetTop(document.all[anchorname]);
    }
    else if (use_gebi) {
        var o = document.getElementById(anchorname);
        x = AnchorPosition_getPageOffsetLeft(o);
        y = AnchorPosition_getPageOffsetTop(o);
    }
    else if (use_css) {
        x = AnchorPosition_getPageOffsetLeft(document.all[anchorname]);
        y = AnchorPosition_getPageOffsetTop(document.all[anchorname]);
    }
    else if (use_layers) {
        var found = 0;
        for (var i = 0; i < document.anchors.length; i++) {
            if (document.anchors[i].name == anchorname) { found = 1; break; }
        }
        if (found == 0) {
            coordinates.x = 0; coordinates.y = 0; return coordinates;
        }
        x = document.anchors[i].x;
        y = document.anchors[i].y;
    }
    else {
        coordinates.x = 0; coordinates.y = 0; return coordinates;
    }
    coordinates.x = x;
    coordinates.y = y;
    return coordinates;
}

// getAnchorWindowPosition(anchorname)
//   This function returns an object having .x and .y properties which are the coordinates
//   of the named anchor, relative to the window
function getAnchorWindowPosition(anchorname) {
    var coordinates = getAnchorPosition(anchorname);
    var x = 0;
    var y = 0;
    if (document.getElementById) {
        if (isNaN(window.screenX)) {
            x = coordinates.x - document.body.scrollLeft + window.screenLeft;
            y = coordinates.y - document.body.scrollTop + window.screenTop;
        }
        else {
            x = coordinates.x + window.screenX + (window.outerWidth - window.innerWidth) - window.pageXOffset;
            y = coordinates.y + window.screenY + (window.outerHeight - 24 - window.innerHeight) - window.pageYOffset;
        }
    }
    else if (document.all) {
        x = coordinates.x - document.body.scrollLeft + window.screenLeft;
        y = coordinates.y - document.body.scrollTop + window.screenTop;
    }
    else if (document.layers) {
        x = coordinates.x + window.screenX + (window.outerWidth - window.innerWidth) - window.pageXOffset;
        y = coordinates.y + window.screenY + (window.outerHeight - 24 - window.innerHeight) - window.pageYOffset;
    }
    coordinates.x = x;
    coordinates.y = y;
    return coordinates;
}

// Functions for IE to get position of an object
function AnchorPosition_getPageOffsetLeft(el) {
    var ol = el.offsetLeft;
    while ((el = el.offsetParent) != null) { ol += el.offsetLeft; }
    return ol;
}
function AnchorPosition_getWindowOffsetLeft(el) {
    return AnchorPosition_getPageOffsetLeft(el) - document.body.scrollLeft;
}
function AnchorPosition_getPageOffsetTop(el) {
    var ot = el.offsetTop;
    while ((el = el.offsetParent) != null) { ot += el.offsetTop; }
    return ot;
}
function AnchorPosition_getWindowOffsetTop(el) {
    return AnchorPosition_getPageOffsetTop(el) - document.body.scrollTop;
}