Check selected / all boxes bookmarklet

check_selected.js

// derived and corrected from https://blogs.uoregon.edu/developments/2010/01/28/check-selected-all-boxes-bookmarklet/

javascript:
    if (typeof(G) == 'undefined' || !G)
        G = true;
    else
        G = false;
    (function() {
        var C;
        (function(W) {
            if (W.frames.length > 0) {
                C = W.frames[i].document.getElementsByTagName('input');
                if (W.frames[i].getSelection && W.frames[i].getSelection().containsNode) {
                    if (W.frames[i].getSelection() != "") {
                        for (var j = 0; j < C.length; j++) {
                            if (W.frames[i].getSelection().containsNode(C[j], true)) {
                                C[j].checked = G;
                            }
                        }
                    } else {
                        for (var j = 0; j < c.length; j++) {
                            C[j].checked = G;
                        }
                    }
                }

            }
        })(window.top);
        C = document.getElementsByTagName('input');
        if (window.getSelection && window.getSelection().containsNode) {
            if (window.getSelection() != "") {
                for (var i = 0; i < C.length; i++) {
                    if (window.getSelection().containsNode(C[i], true)) {
                        C[i].checked = G;
                    }
                }
            } else {
                for (var i = 0; i < C.length; i++) {
                    C[i].checked = G;
                }
            }
        }
    })();