Edit in JSFiddle

$(function () {
    $("#chk1").change(function () {
        var chk = $(this);
        $("#msg").html(
            ".attr('checked'):" + chk.attr("checked") + "<br/>" +
            ".attr('readonly'):" + chk.attr("readonly") + "<br/>" +
            ".attr('disabled'):" + chk.attr("disabled") + "<br/>" +
            ".attr('selected'):" + chk.attr("selected") + "<br/><br/>" +
            ".prop('checked'):" + chk.prop("checked") + "<br/>" +
            ".prop('readonly'):" + chk.prop("readonly") + "<br/>" +
            ".prop('disabled'):" + chk.prop("disabled") + "<br/>" +
            ".prop('selected'):" + chk.prop("selected") + "<br/><br/>" +
            ".is('checked'):" + chk.is(":checked") + "<br/>" +
            ".is('disabled'):" + chk.is(":disabled") + "<br/>" +
            ".is('selected'):" + chk.is(":selected"));
    });

    $("#Btn_Checked").click(function () {
        $("#chk1").prop("checked", function (i, val) {
            return !val;
        }).change();
    });

    $("#Btn_Readonly").click(function () {
        $("#chk1").prop("readonly", function (i, val) {
            return !val;
        }).change();
    });

    $("#Btn_Disabled").click(function () {
        $("#chk1").prop("disabled", function (i, val) {
            return !val;
        }).change();
    });

    $("#Btn_Selected").click(function () {
        $("#chk1").prop("selected", function (i, val) {
            return !val;
        }).change();
    });
});

<input type="checkbox" id="chk1" value="123" />
<input id="Btn_Checked" type="button" value="Checked" />
<input id="Btn_Readonly" type="button" value="Readonly" />
<input id="Btn_Disabled" type="button" value="Disabled" />
<input id="Btn_Selected" type="button" value="Selected" />
<div id="msg"></div>