function my_more_options(){
			add_settings_field('phone','Телефон','display_phone','general');
			register_setting('general','my_phone');
		}
		add_action('admin_init','my_more_options');
		function display_phone(){
			echo "<input type='text' name='my_phone' value='".esc_attr(get_option('my_phone'))."'>";	
		}

<div class="number">
    <span class="minus">-</span>
    <input type="text" value="1" size="5"/>
    <span class="plus">+</span>
</div>

<script type="text/javascript" >
        $(document).ready(function() {
            $('.minus').click(function () {
                var $input = $(this).parent().find('input');
                var count = parseInt($input.val()) - 1;
                count = count < 1 ? 1 : count;
                $input.val(count);
                $input.change();
                return false;
            });
            $('.plus').click(function () {
                var $input = $(this).parent().find('input');
                $input.val(parseInt($input.val()) + 1);
                $input.change();
                return false;
            });
        });