Page navigation

// ==UserScript==
// @id             page-navigation
// @name           Page navigation
// @version        1.0
// @namespace
// @author         Tenno Seremel
// @description
// @include        *
// @run-at         document-start
// @noframes
// ==/UserScript==
(function(){

function on_keypress(e) {
    var target = e.target;
    if (target) {
        var target_name = target.nodeName.toLowerCase();
        if (
            (
                (target_name != "input") && (target_name != "textarea")
            ) || (
                (target_name == "input") && (target.getAttribute("type").toLowerCase() == "submit")
            )
        ) {
            var keys = [
                {key: KeyboardEvent.DOM_VK_RIGHT, rel: "next", ctrl: true, shift: false},
                {key: KeyboardEvent.DOM_VK_LEFT, rel: "prev", ctrl: true, shift: false},
                {key: KeyboardEvent.DOM_VK_LEFT, rel: "previous", ctrl: true, shift: false},
                {key: KeyboardEvent.DOM_VK_UP, rel: "up", ctrl: true, shift: false},
                {key: KeyboardEvent.DOM_VK_RIGHT, rel: "last", ctrl: true, shift: true},
                {key: KeyboardEvent.DOM_VK_LEFT, rel: "first", ctrl: true, shift: true},
            ];
            for(var i=0, len=keys.length; i<len; ++i){
                var current = keys[i];
                if((e.keyCode == current.key) && (e.ctrlKey == current.ctrl) && (e.shiftKey == current.shift) && !e.altKey && !e.metaKey) {
                    e.stopPropagation();
                    e.preventDefault();
                    var link = document.querySelector(':root > head > link[rel="' + current.rel + '"]');
                    if (link !== null) {
                        var link_value = link.getAttribute("href");
                        if (link_value != "") {
                            window.location = link_value;
                            break;
                        }
                    }
                }
            }
        }
    }
}

document.addEventListener("keypress", on_keypress, false)

})();