javascript xmlhttprequest send form

function register() {
var xhr=new  XMLHttpRequest()
var fd="ID="+document.getElementById("ID").value+"&Password="+document.getElementById("Password").value+"&submit=Submit+Query"
xhr.onreadystatechange=function(){
if (xhr.readyState==XMLHttpRequest.DONE) {
document.getElementById("result").innerHTML=xhr.responseText
}
}
xhr.open("POST", "/login")
xhr.setRequestHeader("Content-Type", "Application/x-www-form-urlencoded")
xhr.send(fd)
}