如何使用php / mysql发送jquery ajax调用到服务器上的“收藏”按钮?

I'm looking to POST very simple data to a page for a "favorite" button, called "postData.php" where I already understand how to handle POST data and send it to the server. What I'm unsure of is how to set up the jquery .ajax function to make this work.I'm looking to POST very simple data to a page