selectall / Deselect All click event was not fired if i commect the dialog form it is working

<div id="users-form" title="Users">

<input type="hidden" id="hdnIsEventUserChange" name="hdnIsEventUserChanged" value="false" />

<input id="selectall" type="checkbox" />

Select / Deselect All

<br />

<div id="Users">

//check box list

</div>

</div>

$(function () {

$('#users-form input:checkbox').click(function () { //do not change the name

$("#hdnIsEventUserChange").val(true);

});

$('#selectall:checkbox').click(function () {

$('#Users').find(':checkbox').attr('checked', this.checked);

});

$("#btnAddUser").click(function () {

$("#users-form").dialog("open");

});

$.fx.speeds._default = 1000;

$("#users-form").dialog({

autoOpen: false,

show: "blind",

hide: "explode",

height: 400,

width: 960,

modal: true,

buttons: {

Ok: function () {

var selectedId1 = [];

var count1 = 0;

$('#Users :checked').each(function () {

selectedId1.push($(this).attr('value'));

count1++;

});

if (count1 >= "1") {

$("#UserIds").val(selectedId1.join("|"));

}

$("#users-form").dialog("close");

}

}

});

});