JQUery Must Not Affect Code Behind

[aNubies]

Hi guys I want to know if its possible to execute my code behind (VB code) even the jquery execute first.
To give you a more details on what I am saying, this is what i have

$('#first_div').show();
$('#second_div').hide();

$('#button1').click(function() {
    $('#first_div').slidetoggle('slow');
    $('#second_div').hide();

    $(this).slideToggle('active');
    return false;
});
$('#button2').click(function() {
    $('#second_div').slidetoggle('slow');
    $('#first_div').hide();

    $(this).slideToggle('active');
    return false;
});

with those code my code behind (VB code) doesn't execute anymore. If turn it into return true it will execute however the jquery will not work.

Please help me understand this JQuery . Thank you