Calling wp_insert_post from Jquery -help please

I have a custom content type set up and i want to grab the contents of a div and create a post based on that information. Im using a jquery click action to grab the div contents and then call a php file by POST but this doesn’t seem to be working.

I get the sense that this php file is unaware of the WP functions and variables. Is there someway to call wp_insert_post from Jquery?