How can we send/get the http headers information with AJAX? - ruby-on-rails

Question

Is there any way to send/get the http headers (like, content-type... ) through AJAX?. Then, can please explain me, what will we archive by passing the http headers in AJAX and where will use this technique?.
Thanks

Answer 1

I'm no expert,
But you should look at the AJAX object XmlHttpHeader and the wikipedia article here.
EDIT: quoting the www.w3.org reference:
function test(data) {
// taking care of data
}
function handler() {
if(this.readyState == 4 && this.status == 200) {
// so far so good
if(this.responseXML != null && this.responseXML.getElementById('test').firstChild.data)
// success!
test(this.responseXML.getElementById('test').firstChild.data);
else
test(null);
} else if (this.readyState == 4 && this.status != 200) {
// fetched the wrong page or network error...
test(null);
}
}
var client = new XMLHttpRequest();
client.onreadystatechange = handler;
client.open("GET", "unicorn.xml");
client.send();
If you just want to log a message to the server:
function log(message) {
var client = new XMLHttpRequest();
client.open("POST", "/log");
client.setRequestHeader("Content-Type", "text/plain;charset=UTF-8");
client.send(message);
}
Or if you want to check the status of a document on the server:
function fetchStatus(address) {
var client = new XMLHttpRequest();
client.onreadystatechange = function() {
// in case of network errors this might not give reliable results
if(this.readyState == 4)
returnStatus(this.status);
}
client.open("HEAD", address);
client.send();
}