Form not submitting inside $.ajax success function

I'm validating for duplicate names by using jquery+Ajax. Everything is working fine except that the form is not submitting once everything returns true

What's Happening

• If no name is entered, alert box is showing up stating name is required --> No problem here
• If duplicate name is found, alert box is showing up stating name already exists and form does not submit --> No problem here
• If duplicate name is not found, alert box is showing up (to prove the else part of the condition is working), but the form does not submit. I want the form to go ahead and submit itself in this else part

jQuery Code

$('#form1').submit(function(){

    var name = $('#shelf_name').val();

    if(name == '')
    {
        alert('Shelf name is required');
        $('#shelf_name').focus();
    }
    else
    {                   
        $.ajax({
            type:'post',
            url:'check-duplicate-shelf-name.php',
            data:{'name':name},
            context:this,
            success:function(data)
            {
                if(data == 'stop')
                {
                    alert('Shelf name already exists'); // working if duplicate name is found
                }
                else
                {   
                    alert('else working?'); // alert box is showing up if name is not duplicate                                         
                    this.submit(); // but after alert, this line not executing
                }
            }
        });
    }


    return false;

});

HTML Form Tag

<form action="add-shelf-post.php" method="post" id="form1">

check-duplicate-shelf-name.php Page

<?php

include 'confignew.php';

$name = $_POST['name'];

// peforming database operations
.
.
.

// and then

if($db->num_rows($q) == 0)
{
    echo 'go';
}
else
{
    echo 'stop';
}

I'm missing something very obvious. Hopefully someone here can point that out.

After checking with Firebug in Firefox, I indeed got an error. It didn't show up when I was testing with Chrome. Here is the screenshot.