Modal dialog form is not working with asp.net in Firefox, Chrome

Modal dialog form is not working with asp.net in Firefox, Chrome

I am trying to add modal dialog form to asp.net page and I get an
error where the dialog box appears and disappears without user input.
It seems the disappereance is almost instantaneous and the form does
not stay up on the screen for more than 1 second. This only happens
when I use Firefox and Chrome, but works fine with IE 8.
I am using the example provided <http://jqueryui.com/demos/dialog/
#modal-form>, and I get the same type of error. To reproduce the
error, just add <form> tag after tag <body> (and </form> before
<body>) to example from http://jqueryui.com/demos/dialog/#modal-form
I am new to jQuery and would love to keep using it. Is there something
I am missing? Thanks
Here is my test code.
<!doctype html>
<html lang="en">
<head>
    <title>jQuery UI Dialog - Modal form</title>
    <link type="text/css" href="../../themes/base/ui.all.css"
rel="stylesheet" />
    <script type="text/javascript" src="../../jquery-1.3.2.js"></script>
    <script type="text/javascript" src="../../ui/ui.core.js"></script>
    <script type="text/javascript" src="../../ui/ui.draggable.js"></
script>
    <script type="text/javascript" src="../../ui/ui.resizable.js"></
script>
    <script type="text/javascript" src="../../ui/ui.dialog.js"></script>
    <script type="text/javascript" src="../../ui/effects.core.js"></
script>
    <script type="text/javascript" src="../../ui/effects.highlight.js"></
script>
    <script type="text/javascript" src="../../external/bgiframe/
jquery.bgiframe.js"></script>
    <link type="text/css" href="../demos.css" rel="stylesheet" />
    <style type="text/css">
        body { font-size: 62.5%; }
        label, input { display:block; }
        input.text { margin-bottom:12px; width:95%; padding: .4em; }
        fieldset { padding:0; border:0; margin-top:25px; }
        h1 { font-size: 1.2em; margin: .6em 0; }
        div#users-contain { width: 350px; margin: 20px 0; }
        div#users-contain table { margin: 1em 0; border-collapse: collapse;
width: 100%; }
        div#users-contain table td, div#users-contain table th { border: 1px
solid #eee; padding: .6em 10px; text-align: left; }
        .ui-button { outline: 0; margin:0; padding: .4em 1em .5em; text-
decoration:none; !important; cursor:pointer; position: relative; text-
align: center; }
        .ui-dialog .ui-state-highlight, .ui-dialog .ui-state-error
{ padding: .3em; }
    </style>
    <script type="text/javascript">
    $(function() {
        var name = $("#name"),
            email = $("#email"),
            password = $("#password"),
            allFields = $([]).add(name).add(email).add(password),
            tips = $("#validateTips");
        function updateTips(t) {
            tips.text(t).effect("highlight",{},1500);
        }
        function checkLength(o,n,min,max) {
            if ( o.val().length > max || o.val().length < min ) {
                o.addClass('ui-state-error');
                updateTips("Length of " + n + " must be between "+min+" and "+max
+".");
                return false;
            } else {
                return true;
            }
        }
        function checkRegexp(o,regexp,n) {
            if ( !( regexp.test( o.val() ) ) ) {
                o.addClass('ui-state-error');
                updateTips(n);
                return false;
            } else {
                return true;
            }
        }
            $("#dialog").dialog({
            bgiframe: true,
            autoOpen: false,
            height: 300,
            modal: true,
            buttons: {
                'Create an account': function() {
                    var bValid = true;
                    allFields.removeClass('ui-state-error');
                    bValid = bValid && checkLength(name,"username",3,16);
                    bValid = bValid && checkLength(email,"email",6,80);
                    bValid = bValid && checkLength(password,"password",5,16);
                    bValid = bValid && checkRegexp(name,/^[a-z]([0-9a-z_])+$/
i,"Username may consist of a-z, 0-9, underscores, begin with a
letter.");
                    // From jquery.validate.js (by joern), contributed by Scott
Gonzalez: http://projects.scottsplayground.com/email_address_validation/
                    bValid = bValid && checkRegexp(email,/^((([a-z]|\d|[!#\$%&'\*\+\-
\/=\?\^_`{\|}~]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])+(\.([a-z]|
\d|[!#\$%&'\*\+\-\/=\?\^_`{\|}~]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-
\uFFEF])+)*)|((\x22)((((\x20|\x09)*(\x0d\x0a))?(\x20|\x09)+)?(([\x01-
\x08\x0b\x0c\x0e-\x1f\x7f]|\x21|[\x23-\x5b]|[\x5d-\x7e]|[\u00A0-\uD7FF
\uF900-\uFDCF\uFDF0-\uFFEF])|(\\([\x01-\x09\x0b\x0c\x0d-\x7f]|[\u00A0-
\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF]))))*(((\x20|\x09)*(\x0d\x0a))?(\x20|
\x09)+)?(\x22)))@((([a-z]|\d|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-
\uFFEF])|(([a-z]|\d|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])([a-z]|
\d|-|\.|_|~|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])*([a-z]|\d|
[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])))\.)+(([a-z]|[\u00A0-\uD7FF
\uF900-\uFDCF\uFDF0-\uFFEF])|(([a-z]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-
\uFFEF])([a-z]|\d|-|\.|_|~|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])*
([a-z]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])))\.?$/i,"eg.
ui@jquery.com");
                    bValid = bValid && checkRegexp(password,/^([0-9a-zA-Z])+
$/,"Password field only allow : a-z 0-9");
                    if (bValid) {
                        $('#users tbody').append('<tr>' +
                            '<td>' + name.val() + '</td>' +
                            '<td>' + email.val() + '</td>' +
                            '<td>' + password.val() + '</td>' +
                            '</tr>');
                        $(this).dialog('close');
                    }
                },
                Cancel: function() {
                    $(this).dialog('close');
                }
            },
            close: function() {
                allFields.val('').removeClass('ui-state-error');
            }
        });
        $('#create-user').click(function() {
            $('#dialog').dialog('open');
        })
        .hover(
            function(){
                $(this).addClass("ui-state-hover");
            },
            function(){
                $(this).removeClass("ui-state-hover");
            }
        ).mousedown(function(){
            $(this).addClass("ui-state-active");
        })
        .mouseup(function(){
                $(this).removeClass("ui-state-active");
        });
    });
    </script>
</head>
<body>
<form>
<div class="demo">
<div id="dialog" title="Create new user">
    <p id="validateTips">All form fields are required.
    <form>
    <fieldset>
        <label for="name">Name</label>
        <input type="text" name="name" id="name" class="text ui-widget-
content ui-corner-all" />
        <label for="email">Email</label>
        <input type="text" name="email" id="email" value="" class="text ui-
widget-content ui-corner-all" />
        <label for="password">Password</label>
        <input type="password" name="password" id="password" value=""
class="text ui-widget-content ui-corner-all" />
    </fieldset>
    </form>
</div>
<div id="users-contain" class="ui-widget">
        <h1>Existing Users:</h1>
    <table id="users" class="ui-widget ui-widget-content">
        <thead>
            <tr class="ui-widget-header ">
                <th>Name</th>
                <th>Email</th>
                <th>Password</th>
            </tr>
        </thead>
        <tbody>
            <tr>
                <td>John Doe</td>
                <td>john.doe@example.com</td>
                <td>johndoe1</td>
            </tr>
        </tbody>
    </table>
</div>
<button id="create-user" class="ui-button ui-state-default ui-corner-
all">Create new user</button>
</div><!-- End demo -->
<div class="demo-description">

Use a modal dialog to require that the user enter data during a
multi-step process. Embed form markup in the content area, set the
<code>modal</code> option to true, and specify primary and secondary
user actions with the <code>buttons</code> option.



</div><!-- End demo-description -->
</form>
</body>
</html>
--