Finding all elements with a scroll

Question

What is the most reliable and efficient way to find all elements having a scroll on a page?

---

Currently, I'm thinking about using element.all() with filter() comparing the height and scrollHeight attribute values:

element.all(by.xpath("//*")).filter(function (elm) {
    return protractor.promise.all([
        elm.getAttribute("height"),
        elm.getAttribute("scrollHeight")
    ]).then(function (heights) { 
        return heights[1] > heights[0];
    });
});

But I'm not sure about the correctness and performance of this approach.

Answer 1

This works with both horizontal and vertical scrollbars. The trick is detecting BOTH the too-wide/too-short AND if the computed CSS is going to allow you to display a scrollbar.

var ElementsWithScrolls = (function() {
    var getComputedStyle = document.body && document.body.currentStyle ? function(elem) {
        return elem.currentStyle;
    } : function(elem) {
        return document.defaultView.getComputedStyle(elem, null);
    };

    function getActualCss(elem, style) {
        return getComputedStyle(elem)[style];
    }

    function isXScrollable(elem) {
        return elem.offsetWidth < elem.scrollWidth &&
            autoOrScroll(getActualCss(elem, 'overflow-x'));
    }

    function isYScrollable(elem) {
        return elem.offsetHeight < elem.scrollHeight &&
            autoOrScroll(getActualCss(elem, 'overflow-y'));
    }

    function autoOrScroll(text) {
        return text == 'scroll' || text == 'auto';
    }

    function hasScroller(elem) {
        return isYScrollable(elem) || isXScrollable(elem);
    }
    return function ElemenetsWithScrolls() {
        return [].filter.call(document.querySelectorAll('*'), hasScroller);
    };
})();

ElementsWithScrolls();