logging in
add_action('admin_print_styles', 'mitsol_admin_css_all_page');
this action - "admin_print_styles" is responsible for injecting script and style
files in head section in your admin page.So now you will add above registered function
as follows -
function mitsol_admin_css_all_page() {  ÂÂ
 wp_enqueue_script('jquery');
 wp_register_script('mitsol_feed_bootstrap_js', plugins_url('js/my_js_file.js', __FILE__), array("jquery"));
 wp_enqueue_script('mitsol_feed_bootstrap_js');
  ÂÂ
 wp_register_style($handle = 'mitsol_feed', $src = plugins_url('css/custom_css.css', __FILE__), $deps = array(), $ver = '1.0.0', $media = 'all');
 wp_enqueue_style('mitsol_feed');
}
"wp_enqueue_script" gonna register jquery at first ÂÂ
"wp_register_script" will register custom javascript file for your admin page, for
this, in addition, you have to include "wp_enqueue_script" also as above function shows.
In the same way follow the last two lines above for injecting style files.
