不打印用户选择的帖子数

Question

I want to create functionality, where user can select how many posts to be displayed.Now, If i have 10 posts and want to display only 3, it is not possible. It will show me all the existed posts. Here's my JavaScript:

buttons: {
                'Save': function () {

                    var num        = $(document).find('#dx_blog_posts_num').val();
                    var image      = $(document).find('#dx_blog_featured_image').is(':checked');
                    var excerpt    = $(document).find('#dx_blog_excerpt').is(':checked');

                    parentDiv.attr('data-blog-image', image);
                    parentDiv.attr('data-blog-excerpt', excerpt);

                    var check   = parentDiv.find('.hidden').length;

                    if(!check) {
                        parentDiv.append('<div class="hidden">' + num + '</div>');
                    }
                    else{
                        parentDiv.find('.hidden').html(num);
                    }

                    jQuery(this).dialog('destroy');
                }

jQuery(this).dialog('destroy');
      }

And the HTML:

<div id="dx-blog-dialog" title="<?php _e( 'Blog', 'dxeasypb' ); ?>">
    <div>
        <label for="dx_blog_posts_num"><?php _e( 'Number of Posts', 'dxeasypb' ); ?></label>&nbsp;&nbsp;<input type="text" id="dx_blog_posts_num">
    </div>  

    <div>
        <input type="checkbox" id="dx_blog_featured_image"><label for="dx_blog_featured_image"><?php _e( 'Display Featured Image', 'dxeasypb' ); ?></label>
    </div>

    <div>
        <input type="checkbox" id="dx_blog_excerpt"><label for="dx_blog_excerpt"><?php _e( 'Display Full Content', 'dxeasypb' ); ?></label>
    </div>
</div>