function getHTMLElementContentRect(target) {
        // Client width & height properties can't be
        // used exclusively as they provide rounded values.
        var clientWidth = target.clientWidth, clientHeight = target.clientHeight;
        // By this condition we can catch all non-replaced inline, hidden and
        // detached elements. Though elements with width & height properties less
        // than 0.5 will be discarded as well.
        //
        // Without it we would need to implement separate methods for each of
        // those cases and it's not possible to perform a precise and performance
        // effective test for hidden elements. E.g. even jQuery's ':visible' filter
        // gives wrong results for elements with width & height less than 0.5.
        if (!clientWidth && !clientHeight) {
            return emptyRect;
        }
        var styles = getWindowOf(target).getComputedStyle(target);
        var paddings = getPaddings(styles);
        var horizPad = paddings.left + paddings.right;
        var vertPad = paddings.top + paddings.bottom;
        // Computed styles of width & height are being used because they are the
        // only dimensions available to JS that contain non-rounded values. It could
        // be possible to utilize the getBoundingClientRect if only it's data wasn't
        // affected by CSS transformations let alone paddings, borders and scroll bars.
        var width = toFloat(styles.width), height = toFloat(styles.height);
        // Width & height include paddings and borders when the 'border-box' box
        // model is applied (except for IE).
        if (styles.boxSizing === 'border-box') {
            // Following conditions are required to handle Internet Explorer which
            // doesn't include paddings and borders to computed CSS dimensions.
            //
            // We can say that if CSS dimensions + paddings are equal to the "client"
            // properties then it's either IE, and thus we don't need to subtract
            // anything, or an element merely doesn't have paddings/borders styles.
            if (Math.round(width + horizPad) !== clientWidth) {
                width -= getBordersSize(styles, 'left', 'right') + horizPad;
            }
            if (Math.round(height + vertPad) !== clientHeight) {
                height -= getBordersSize(styles, 'top', 'bottom') + vertPad;
            }
        }
        // Following steps can't be applied to the document's root element as its
        // client[Width/Height] properties represent viewport area of the window.
        // Besides, it's as well not necessary as the <html> itself neither has
        // rendered scroll bars nor it can be clipped.
        if (!isDocumentElement(target)) {
            // In some browsers (only in Firefox, actually) CSS width & height
            // include scroll bars size which can be removed at this step as scroll
            // bars are the only difference between rounded dimensions + paddings
            // and "client" properties, though that is not always true in Chrome.
            var vertScrollbar = Math.round(width + horizPad) - clientWidth;
            var horizScrollbar = Math.round(height + vertPad) - clientHeight;
            // Chrome has a rather weird rounding of "client" properties.
            // E.g. for an element with content width of 314.2px it sometimes gives
            // the client width of 315px and for the width of 314.7px it may give
            // 314px. And it doesn't happen all the time. So just ignore this delta
            // as a non-relevant.
            if (Math.abs(vertScrollbar) !== 1) {
                width -= vertScrollbar;
            }
            if (Math.abs(horizScrollbar) !== 1) {
                height -= horizScrollbar;
            }
        }
        return createRectInit(paddings.left, paddings.top, width, height);
    }
Calculates content rectangle of provided HTMLElement.

@param {HTMLElement} target - Element for which to calculate the content rectangle.
@returns {DOMRectInit}