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 permit you to show 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();