CMS Drupal Mastering Development

How Advagg build their advagg_get_js and called the advagg_js_pre_render [duplicate]

I have done a bit of research in Advagg , I dont understand how they override the drupal_get_js and implemented their advagg_get_js and from there invoked advagg_pre_render_scripts which overrides drupal_pre_render_script. How they did it? And , I made a module and when altering hook_element_info , I did not get the $type[‘script’] there, Why is that?Can […]