change an objects color after scrolling

hey I what a make a object which can change color after scrolling (down) 100px and change back to default after srolling back (up). Im using this code but not working

JQuary:

$(window).scroll(function() {

//After scrolling 100px from the top...
if ( $(window).scrollTop() >= 100 ) {
$('#menu').css('background', '#fff');

//Otherwise remove inline styles and thereby revert to original stying
} else {
$('#menu').removeAttr('style');

}
});​

and my html:

<header>
<table>
<tr>
<td  id="menu" class="title">
TITLE
</td>
<td style="width:40px;">
<div class=" ico">    
<img src="search.svg" alt="search" style="width: 25px;" />
</div>
</td>
<td style="width: 40px;">
<div class=" ico">
<img src="menu.svg" alt="search" style="width: 25px;"/>
</div>
</td>
</tr>
</table>
</header>