/**
* --------------------------------------------------------------------
* jQuery-Plugin "preloadCssImages"
* by Scott Jehl, scott@filamentgroup.com
* http://www.filamentgroup.com
* reference article: http://www.filamentgroup.com/lab/update_automatically_preload_images_from_css_with_jquery/
* demo page: http://www.filamentgroup.com/examples/preloadImages/index_v2.php
* 
* Copyright (c) 2008 Filament Group, Inc
* Dual licensed under the MIT (filamentgroup.com/examples/mit-license.txt) and GPL (filamentgroup.com/examples/gpl-license.txt) licenses.
*
* Version: 3.0, 06.21.2008
* Changelog:
* 	02.20.2008 initial Version 1.0
*    06.04.2008 Version 2.0 : removed need for any passed arguments. Images load from any and all directories.
*    06.21.2008 Version 3.0 : Added options for loading status. Fixed IE abs image path bug (thanks Sam Pohlenz).
* --------------------------------------------------------------------
*/
jQuery.preloadCssImages = function(settings) {
    var settings = jQuery.extend({
        statusTextEl: null,
        statusBarEl: null
    }, settings);

    var allImgs = []; //new array for all the image urls  
    var k = 0; //iterator for adding images
    var sheets = document.styleSheets; //array of stylesheets

    for (var i = 0; i < sheets.length; i++) {//loop through each stylesheet
        var cssPile = ''; //create large string of all css rules in sheet
        var csshref = (sheets[i].href) ? sheets[i].href : 'window.location.href';
        var baseURLarr = csshref.split('/'); //split href at / to make array
        baseURLarr.pop(); //remove file path from baseURL array
        var baseURL = baseURLarr.join('/'); //create base url for the images in this sheet (css file's dir)
        if (baseURL != "") baseURL += '/'; //tack on a / if needed
        if (document.styleSheets[i].cssRules) {//w3
            var thisSheetRules = document.styleSheets[i].cssRules; //w3
            for (var j = 0; j < thisSheetRules.length; j++) {
                cssPile += thisSheetRules[j].cssText;
            }
        }
        else {
            cssPile += document.styleSheets[i].cssText;
        }

        //parse cssPile for image urls and load them into the DOM
        var imgUrls = cssPile.match(/[^\(]+\.(gif|jpg|jpeg|png)/g); //reg ex to get a string of between a "(" and a ".filename"
        var loaded = 0; //number of images loaded
        if (imgUrls != null && imgUrls.length > 0 && imgUrls != '') {//loop array\
            var arr = jQuery.makeArray(imgUrls); //create array from regex obj	 
            jQuery(arr).each(function() {
                allImgs[k] = new Image(); //new img obj
                allImgs[k].src = (this.charAt(0) == '/' || this.match('http://')) ? this : baseURL + this; //set src either absolute or rel to css dir

                $(allImgs[k]).load(function() {
                    loaded++;
                    //send updates to status elements if applicable
                    if (settings.statusTextEl) {
                        $(settings.statusTextEl).html('<span class="numLoaded">' + loaded + '</span> of <span class="numTotal">' + allImgs.length + '</span> loaded (<span class="percentLoaded">' + (loaded / allImgs.length * 100).toFixed(0) + '%</span>) <span class="currentImg">Now Loading: <span>' + allImgs[loaded - 1].src.split('/')[allImgs[loaded - 1].src.split('/').length - 1] + '</span></span>');
                    }
                    if (settings.statusBarEl) {
                        var barWidth = $(settings.statusBarEl).width();
                        $(settings.statusBarEl).css('background-position', -(barWidth - (barWidth * loaded / allImgs.length).toFixed(0)) + 'px 50%');
                    }
                });
                k++;
            });
        }
    } //loop
    return allImgs;
}