JS to scale img to browser

gistfile1.js

    var sizeSlideAsset = function (slideNode) {
        var img = slideNode.one('.assetWrap img');
        var assetWrap = img.ancestor('.assetWrap');

        var wrapWidth = assetWrap.get('offsetWidth');
        var wrapHeight = assetWrap.get('offsetHeight');

        var imgWidth = Y.Util.getClassValue(img, 'imgW');
        var imgHeight = Y.Util.getClassValue(img, 'imgH');

        var targetDimensions = getImageDimensionsToFitContainer(imgWidth, imgHeight, wrapWidth, wrapHeight);

        img.setStyles({
            'width':  targetDimensions.width + 'px',
            'height': targetDimensions.height + 'px'
        });
    }

    var getImageDimensionsToFitContainer = function (imgWidth, imgHeight, wrapWidth, wrapHeight) {

        var targetImgHeight = imgHeight;
        var targetImgWidth  = imgWidth;

        var verticalScalingFactor = (wrapHeight/imgHeight);

        // Scale
        if ((imgWidth*verticalScalingFactor) <= wrapWidth) {
            // Height is the limiting dimension
            targetImgWidth = Math.round(imgWidth * verticalScalingFactor);
            targetImgHeight = wrapHeight;
            Y.log("Fitting vertically, scale=" + verticalScalingFactor + ". W=" + targetImgWidth + " H=" + targetImgHeight);
        }
        else if ((imgWidth*verticalScalingFactor) > wrapWidth) {
            var horizontalScalingFactor = (wrapWidth/imgWidth);
            // Width is the limiting dimension
            targetImgWidth = wrapWidth;
            targetImgHeight = Math.round(imgHeight * horizontalScalingFactor);
            Y.log("Fitting horizontally, scale=" + horizontalScalingFactor + ". W=" + targetImgWidth + " H=" + targetImgHeight);
        }

        return {
            width:  targetImgWidth,
            height: targetImgHeight
        };
    }