Issues with jQuery.animate in IE8

Question

Hi guys, I'm trying to display screenshots of an iPhone application through a scrollable background using jQuery. The code I wrote works fine in FF and Safari, but IE throws an "Invalid Argument" error.

/ EDIT: I decided that I would add what IE really does when it fails. It jumps to the second screenshot and gives an error. Each other browser animates smoothly, but IE does not come to life, it just jumps to the second screenshot, and then gives an error.

Here is my code:

var scrollInterval = 5000; // scroll every 5 seconds

    // set the default position
    var current = 1284;

    var screenScroll = function(){
        var imageSize = 1284;
        var screenshotWidth = 214;
        current -= screenshotWidth;

        if ( current < screenshotWidth) {
            current = imageSize;
        }

        var bgPos = current + "px top";
        $("#screenshotDiv").animate({backgroundPosition:bgPos}, 500);

    }

    $(document).ready(function() {
        //Calls the scrolling function repeatedly
        var init = setInterval(screenScroll, scrollInterval);
    });

Answer 1

IE8, jQuery. , jQuery IE. , IE -, .

, . script jQuery, . , , :

/**
 * @author Alexander Farkas
 * v. 1.21
 */

(function($) {
    if(!document.defaultView || !document.defaultView.getComputedStyle){ // IE6-IE8
        var oldCurCSS = jQuery.curCSS;
        jQuery.curCSS = function(elem, name, force){
            if(name === 'background-position'){
                name = 'backgroundPosition';
            }
            if(name !== 'backgroundPosition' || !elem.currentStyle || elem.currentStyle[ name ]){
                return oldCurCSS.apply(this, arguments);
            }
            var style = elem.style;
            if ( !force && style && style[ name ] ){
                return style[ name ];
            }
            return oldCurCSS(elem, 'backgroundPositionX', force) +' '+ oldCurCSS(elem, 'backgroundPositionY', force);
        };
    }

    var oldAnim = $.fn.animate;
    $.fn.animate = function(prop){
        if('background-position' in prop){
            prop.backgroundPosition = prop['background-position'];
            delete prop['background-position'];
        }
        if('backgroundPosition' in prop){
            prop.backgroundPosition = '('+ prop.backgroundPosition;
        }
        return oldAnim.apply(this, arguments);
    };

    function toArray(strg){
        strg = strg.replace(/left|top/g,'0px');
        strg = strg.replace(/right|bottom/g,'100%');
        strg = strg.replace(/([0-9\.]+)(\s|\)|$)/g,"$1px$2");
        var res = strg.match(/(-?[0-9\.]+)(px|\%|em|pt)\s(-?[0-9\.]+)(px|\%|em|pt)/);
        return [parseFloat(res[1],10),res[2],parseFloat(res[3],10),res[4]];
    }

    $.fx.step. backgroundPosition = function(fx) {
        if (!fx.bgPosReady) {
            var start = $.curCSS(fx.elem,'backgroundPosition');

            if(!start){//FF2 no inline-style fallback
                start = '0px 0px';
            }

            start = toArray(start);

            fx.start = [start[0],start[2]];

            var end = toArray(fx.options.curAnim.backgroundPosition);
            fx.end = [end[0],end[2]];

            fx.unit = [end[1],end[3]];
            fx.bgPosReady = true;
        }
        //return;
        var nowPosX = [];
        nowPosX[0] = ((fx.end[0] - fx.start[0]) * fx.pos) + fx.start[0] + fx.unit[0];
        nowPosX[1] = ((fx.end[1] - fx.start[1]) * fx.pos) + fx.start[1] + fx.unit[1];           
        fx.elem.style.backgroundPosition = nowPosX[0]+' '+nowPosX[1];

    };
})(jQuery);

IE8 . IE7, 13% IE, ... .

Answer 2

IE , {: 500}, ? ?

, , backgroundPosition IE8 : http://reference.sitepoint.com/css/background-position

, ?

Answer 3

The solution regarding the script is the work of Alexander Farkas, but first you need to fix it a bit (as I needed it to work). Line:

var end = toArray(fx.options.curAnim.backgroundPosition);

need to change to

var end = toArray(fx.end);