javascript create form and post

var form = document.createElement("form");

form.setAttribute("method", "post");

form.setAttribute("action","<?php echo $_SERVER['PHP_SELF'];?>");        

document.body.appendChild(form);                        

   

var input = document.createElement("input");  

input.setAttribute("type", "hidden");                 

input.setAttribute("name", "message_type");                        

input.setAttribute("value", 0);                          

form.appendChild(input);

form.submit();