wordpress custom list table bulk actions

i extended wordpress custom list table class for my plugin. everything works perfectly. Then i want to customize my bulk actions. in bulk action (ie. list table submit) there are 8 POST variable and 1 GET variable. can i include one more post variable with this? i tried with my js file but the var_dump shows the default post and GET variables only. with out this wp-list-table submit i got my custom post and get variables. why this is happened? where this global variables comes from actually?