Send Post data using XMLHTTPREQUEST?

Can we send post data to a page using XMLHTTPREQUEST like we do with curl is it possible?

Like I want to send name,address,city to a php file using xmhttprequest can I do that? Can someone please tell me how to do it and also I want to send data in background

using only js and assuming you have a properly created XHR object stored in a variable called "xmlHttp":

function post(){
    if(xmlHttp){
        var url = 'submit.php'; // the url you want to submit to
        var yourdata = document.getElemenyById('yourForm').serialize();
        xmlhttp.onreadystatechange = XMLHttpRequestChange; 
        xmlhttp.open("POST", url, true);
        xmlhttp.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
        xmlhttp.send(yourdata);

Observations:

- url can be any URL that will handle the POST, no biggie here

- yourdata must be a set of "GET-style" key-value pairs; either you can format them by hand ie:

var yourdata = "name=myname&age=myage&foo=bar";

if you do it by hand dont forget to URLEncode the values.

- the better way to do the above step is to use the serialize() function instead:

it can accept either a form as a parameter (assign an ID to the form and serialize the form based on its ID as in my example or it can also accept an associative array as a parameter and it will produce "POST-SAFE" content