/*************************************************************
* NLB Background Color Fader v1.0
* Author: Justin Barlow - www.netlobo.com
*
* Description:
* The Background Color Fader allows you to gradually fade the
* background of any HTML element.
*
* Usage:
* Call the Background Color Fader as follows:
*   NLBfadeBg( elementId, startBgColor, endBgColor, fadeTime );
*
* Description of Parameters
*   elementId - The id of the element you wish to fade the
*             background of.
*   startBgColor - The background color you wish to start the
*             fade from.
*   endBgColor - The background color you want to fade to.
*   fadeTime - The duration of the fade in milliseconds.
*************************************************************/

var nlbFade_hextable = ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F']; // used for RGB to Hex and Hex to RGB conversions
var nlbFade_elemTable = new Array(); // global array to keep track of faded elements
var nlbFade_t = new Array(); // global array to keep track of fading timers
function NLBfadeBg(elementId, startBgColor, endBgColor, fadeTime) {
    var timeBetweenSteps = Math.round(Math.max(fadeTime / 300, 30));
    var nlbFade_elemTableId = nlbFade_elemTable.indexOf(elementId);
    if (nlbFade_elemTableId > -1) {
        for (var i = 0; i < nlbFade_t[nlbFade_elemTableId].length; i++)
            clearTimeout(nlbFade_t[nlbFade_elemTableId][i]);
    }
    else {
        nlbFade_elemTable.push(elementId);
        nlbFade_elemTableId = nlbFade_elemTable.indexOf(elementId);
    }
    var startBgColorRGB = hexToRGB(startBgColor);
    var endBgColorRGB = hexToRGB(endBgColor);
    var diffRGB = new Array();
    for (var i = 0; i < 3; i++)
        diffRGB[i] = endBgColorRGB[i] - startBgColorRGB[i];
    var steps = Math.ceil(fadeTime / timeBetweenSteps);
    var nlbFade_s = new Array();
    for (var i = 1; i <= steps; i++) {
        var changes = new Array();
        for (var j = 0; j < diffRGB.length; j++)
            changes[j] = startBgColorRGB[j] + Math.round((diffRGB[j] / steps) * i);
        if (i == steps)
            nlbFade_s[i - 1] = setTimeout('document.getElementById("' + elementId + '").style.backgroundColor = "' + endBgColor + '";', timeBetweenSteps * (i - 1));
        else
            nlbFade_s[i - 1] = setTimeout('document.getElementById("' + elementId + '").style.backgroundColor = "' + RGBToHex(changes) + '";', timeBetweenSteps * (i - 1));
    }
    nlbFade_t[nlbFade_elemTableId] = nlbFade_s;
}
function hexToRGB(hexVal) {
    hexVal = hexVal.toUpperCase();
    if (hexVal.substring(0, 1) == '#')
        hexVal = hexVal.substring(1);
    var hexArray = new Array();
    var rgbArray = new Array();
    hexArray[0] = hexVal.substring(0, 2);
    hexArray[1] = hexVal.substring(2, 4);
    hexArray[2] = hexVal.substring(4, 6);
    for (var k = 0; k < hexArray.length; k++) {
        var num = hexArray[k];
        var res = 0;
        var j = 0;
        for (var i = num.length - 1; i >= 0; i--)
            res += parseInt(nlbFade_hextable.indexOf(num.charAt(i))) * Math.pow(16, j++);
        rgbArray[k] = res;
    }
    return rgbArray;
}
function RGBToHex(rgbArray) {
    var retval = new Array();
    for (var j = 0; j < rgbArray.length; j++) {
        var result = new Array();
        var val = rgbArray[j];
        var i = 0;
        while (val > 16) {
            result[i++] = val % 16;
            val = Math.floor(val / 16);
        }
        result[i++] = val % 16;
        var out = '';
        for (var k = result.length - 1; k >= 0; k--)
            out += nlbFade_hextable[result[k]];
        retval[j] = padLeft(out, '0', 2);
    }
    out = '#';
    for (var i = 0; i < retval.length; i++)
        out += retval[i];
    return out;
}
if (!Array.prototype.indexOf) {
    Array.prototype.indexOf = function(val, fromIndex) {
        if (typeof (fromIndex) != 'number') fromIndex = 0;
        for (var index = fromIndex, len = this.length; index < len; index++)
            if (this[index] == val) return index;
        return -1;
    }
}
function padLeft(string, character, paddedWidth) {
    if (string.length >= paddedWidth)
        return string;
    else {
        while (string.length < paddedWidth)
            string = character + string;
    }
    return string;
}