need help understanding part of code

need help understanding part of code

I have some code which takes values of a form and submits to a database. In part of it, I am not sure what the rand.Math.random() is doing. I understand everything else. I received this code from a tutorial I found online and was curious. Here is the entire line of code.

  1. $.post("login.php", {username:$('#username').val(),password:$('#password').val(),editor_name:$('#editor_name').val(),rand:Math.random() } ,function(data)