/* Copyright (c) 2006 Brandon Aaron (http://brandonaaron.net) 
 * Dual licensed under the MIT (http://www.opensource.org/licenses/mit-license.php)  
 * and GPL (http://www.opensource.org/licenses/gpl-license.php) licenses. 
 * 
 * $LastChangedDate: 2007-07-21 18:44:59 -0500 (Sat, 21 Jul 2007) $ 
 * $Rev: 2446 $ 
 * 
 * Version 2.1.1 
 */ 
 
(function($){ 
 
/** 
 * The bgiframe is chainable and applies the iframe hack to get  
 * around zIndex issues in IE6. It will only apply itself in IE6  
 * and adds a class to the iframe called 'bgiframe'. The iframe 
 * is appeneded as the first child of the matched element(s)  
 * with a tabIndex and zIndex of -1. 
 *  
 * By default the plugin will take borders, sized with pixel units, 
 * into account. If a different unit is used for the border's width, 
 * then you will need to use the top and left settings as explained below. 
 * 
 * NOTICE: This plugin has been reported to cause perfromance problems 
 * when used on elements that change properties (like width, height and 
 * opacity) a lot in IE6. Most of these problems have been caused by  
 * the expressions used to calculate the elements width, height and  
 * borders. Some have reported it is due to the opacity filter. All  
 * these settings can be changed if needed as explained below. 
 * 
 * @example $('div').bgiframe(); 
 * @before <div><p>Paragraph</p></div> 
 * @result <div><iframe class="bgiframe".../><p>Paragraph</p></div> 
 * 
 * @param Map settings Optional settings to configure the iframe. 
 * @option String|Number top The iframe must be offset to the top 
 *              by the width of the top border. This should be a negative  
 *      number representing the border-top-width. If a number is  
 *              is used here, pixels will be assumed. Otherwise, be sure 
 *              to specify a unit. An expression could also be used.  
 *              By default the value is "auto" which will use an expression  
 *              to get the border-top-width if it is in pixels. 
 * @option String|Number left The iframe must be offset to the left 
 *              by the width of the left border. This should be a negative  
 *      number representing the border-left-width. If a number is  
 *              is used here, pixels will be assumed. Otherwise, be sure 
 *              to specify a unit. An expression could also be used.  
 *              By default the value is "auto" which will use an expression  
 *              to get the border-left-width if it is in pixels. 
 * @option String|Number width This is the width of the iframe. If 
 *              a number is used here, pixels will be assume. Otherwise, be sure 
 *              to specify a unit. An experssion could also be used. 
 *              By default the value is "auto" which will use an experssion 
 *              to get the offsetWidth. 
 * @option String|Number height This is the height of the iframe. If 
 *              a number is used here, pixels will be assume. Otherwise, be sure 
 *              to specify a unit. An experssion could also be used. 
 *              By default the value is "auto" which will use an experssion 
 *              to get the offsetHeight. 
 * @option Boolean opacity This is a boolean representing whether or not 
 *              to use opacity. If set to true, the opacity of 0 is applied. If 
 *              set to false, the opacity filter is not applied. Default: true. 
 * @option String src This setting is provided so that one could change  
 *              the src of the iframe to whatever they need. 
 *              Default: "javascript:false;" 
 * 
 * @name bgiframe 
 * @type jQuery 
 * @cat Plugins/bgiframe 
 * @author Brandon Aaron (brandon.aaron@gmail.com || http://brandonaaron.net) 
 */ 
$.fn.bgIframe = $.fn.bgiframe = function(s) { 
        // This is only for IE6 
        if ( $.browser.msie && /6.0/.test(navigator.userAgent) ) { 
                s = $.extend({ 
                        top     : 'auto', // auto == .currentStyle.borderTopWidth 
                        left    : 'auto', // auto == .currentStyle.borderLeftWidth 
                        width   : 'auto', // auto == offsetWidth 
                        height  : 'auto', // auto == offsetHeight 
                        opacity : true, 
                        src     : 'javascript:false;' 
                }, s || {}); 
                var prop = function(n){return n&&n.constructor==Number?n+'px':n;}, 
                    html = '<iframe class="bgiframe"frameborder="0"tabindex="-1"src="'+s.src+'"'+ 
                               'style="display:block;position:absolute;z-index:-1;'+ 
                                       (s.opacity !== false?'filter:Alpha(Opacity=\'0\');':'')+ 
                                               'top:'+(s.top=='auto'?'expression(((parseInt(this.parentNode.currentStyle.borderTopWidth)||0)*-1)+\'px\')':prop(s.top))+';'+ 
                                               'left:'+(s.left=='auto'?'expression(((parseInt(this.parentNode.currentStyle.borderLeftWidth)||0)*-1)+\'px\')':prop(s.left))+';'+ 
                                               'width:'+(s.width=='auto'?'expression(this.parentNode.offsetWidth+\'px\')':prop(s.width))+';'+ 
                                               'height:'+(s.height=='auto'?'expression(this.parentNode.offsetHeight+\'px\')':prop(s.height))+';'+ 
                                        '"/>'; 
                return this.each(function() { 
                        if ( $('> iframe.bgiframe', this).length == 0 ) 
                                this.insertBefore( document.createElement(html), this.firstChild ); 
                }); 
        } 
        return this; 
}; 
 
})(jQuery);