change checkbox jquery alert

1//jQuery listen for checkbox change
2$("#myCheckBoxID").change(function() {
3    if(this.checked) {
4        //I am checked
5    }else{
6        //I'm not checked
7    }
8});

1$(document).ready(function() {
2    //set initial state.
3    $('#textbox1').val($(this).is(':checked'));
4
5    $('#checkbox1').change(function() {
6        if($(this).is(":checked")) {
7            var returnVal = confirm("Are you sure?");
8            $(this).attr("checked", returnVal);
9        }
10        $('#textbox1').val($(this).is(':checked'));        
11    });
12});

1$('#checkbox1').mousedown(function() {
2    if (!$(this).is(':checked')) {
3        this.checked = confirm("Are you sure?");
4        $(this).trigger("change");
5    }
6});

1$(document).ready(function() {
2    //set initial state.
3    $('#textbox1').val(this.checked);
4
5    $('#checkbox1').change(function() {
6        if(this.checked) {
7            var returnVal = confirm("Are you sure?");
8            $(this).prop("checked", returnVal);
9        }
10        $('#textbox1').val(this.checked);        
11    });
12});