Super simple autofiller, run through http://bookmarklets.org/maker/

autofill.js

(function ($) {
    function randInt(max, min) {
        max = max || 1;
        min = min || 0;
        return parseInt(Math.random() * (max - min)) + min;
    }

    var letters = [
        "a", "b", "c", "d", "e", "f", "g", "h",
        "i", "j", "k", "l", "m", "n", "o", "p",
        "q", "r", "s", "t", "u", "v", "w", "x",
        "y", "z", " "
    ];

    $("input[type=\"number\"]").each(function () {
        var $this = $(this);
        var max = $this.attr("max") || 99999999999;
        var min = $this.attr("min") || 0;
        $(this).val(randInt(max, min));
    });

    $("input[type=\"text\"]").each(function () {
        var text = new Array(randInt(30, 1))
            .fill(undefined)
            .reduce(function (acc) {
                return acc + letters[randInt(letters.length)];
            }, "");
        $(this).val(text);
    });

    $("select").each(function () {
        var $this = $(this);
        var options = $this.find("option");
        $(options[randInt(options.length)]).prop("selected", true);
        $this.trigger("change");
    });

    $("input[type=\"email\"]").each(function () {
        var email = new Array(randInt(15, 10))
            .fill(undefined)
            .reduce(function (acc) {
                return acc + letters[randInt(letters.length)];
            }, "")
            .replace(' ', '_')
            .concat('@dev.autofill');
        $(this).val(email);
    });

    var passwordSeed = ["a", "b", "c", 1, 2, 3, '!', '@', '#'];
    var password = new Array(randInt(20, 15))
        .fill(undefined)
        .reduce(function (acc) {
            return acc + passwordSeed[randInt(passwordSeed.length)];
        }, "");
    var passwords = $("input[type=\"password\"]");
    passwords.each(function () {
        $(this).val(password);
    });
    if (passwords.length && confirm("Copy password?")) {
        var textArea = document.createElement("textarea");
        textArea.innerText = password;
        document.body.appendChild(textArea);
        textArea.select();
        try {
            if (!document.execCommand("copy")) {
                alert("Can't copy.");
            }
        } catch (err) {
            alert("Could not copy password:" + err.message);
        }
        document.body.removeChild(textArea);
    }
})(jQuery);