javascript – 从FF / Webkit中的像素位置创建折叠范围

if (!document.caretRangeFromPoint) {
    document.caretRangeFromPoint = function(x,y) {
        var log = "";

        function inRect(x,y,rect) {
            return x >= rect.left && x <= rect.right && y >= rect.top && y <= rect.bottom;
        }

        function inObject(x,object) {
            var rects = object.getClientRects();
            for (var i = rects.length; i--;)
                if (inRect(x,rects[i]))
                    return true;
            return false;
        }

        function getTextNodes(node,x,y) {
            if (!inObject(x,nodE))
                return [];

            var result = [];
            node = node.firstChild;
            while (nodE) {
                if (node.nodeType == 3)
                    result.push(nodE);
                if (node.nodeType == 1)
                    result = result.concat(getTextNodes(node,y));

                node = node.nextSibling;
            }

            return result;
        }

        var element = document.elementFromPoint(x,y);
        var nodes = getTextNodes(element,y);
        if (!nodes.length)
            return null;
        var node = nodes[0];

        var range = document.createRange();
        range.setStart(node,0);
        range.setEnd(node,1);

        for (var i = nodes.length; i--;) {
            var node = nodes[i],text = node.nodeValue;


            range = document.createRange();
            range.setStart(node,0);
            range.setEnd(node,text.length);

            if (!inObject(x,rangE))
                conTinue;

            for (var j = text.length; j--;) {
                if (text.charCodeAt(j) <= 32)
                    conTinue;

                range = document.createRange();
                range.setStart(node,j);
                range.setEnd(node,j + 1);

                if (inObject(x,rangE)) {
                    range.setEnd(node,j);
                    return range;
                }
            }
        }

        return range;
    };
}