Search not working...

functions.php

// SEARCH FORM HEADER
function search_form_header( $form ) {
    $form = '<form method="get" id="header-searchform" action="' . home_url( '/' ) . '" >
    <div>
    	<div class="searchform-left"></div>
    	<input class="searchform-mid clearit" type="text" name="search" id="search-header" value="Search" />
    	<div class="searchform-right"></div>	
    </div>
    </form>';
    return $form;
}
add_filter( 'get_search_form', 'search_form_header' );