通过XMLHttpRequest提交表单

我想使用XMLHttpRequest来获取远程PHP文件的响应并将其显示在我的页面上。

当然，我的问题是：表单的数据没有提交到那个远程PHP页面。

我该如何做到这一点？谢谢

<form name="creation" action="" method="post">
E-mail: 
<input required type="text" name="emailCreation" onchange="emailValidate();" 
onkeypress="this.onchange();" onpaste="this.onchange();" oninput="this.onchange();">
<span id="emailRegexJavascriptResponse"></span>
<br>
Username: <input required type="text" name="userCreation" onchange="userValidate();" 
onkeypress="this.onchange();" onpaste="this.onchange();" oninput="this.onchange();">
<span id="userRegexJavascriptResponse"></span>
<br>
Password: <input required type="text" name="passwordCreation" onchange="passwordValidate();" 
onkeypress="this.onchange();" onpaste="this.onchange();" oninput="this.onchange();">
<span id="passwordJavascriptResponse"></span>
<br>
<input type="button" value="Submit" onclick="creationResult();">

<div id="here"></div><div id="here2"></div>
<!-- End -->

<script type="text/javascript">

function creationResult() {
    if (window.XMLHttpRequest) {
        // code for IE7+, Firefox, Chrome, Opera, Safari
        xmlhttp=new XMLHttpRequest();
    } else { // code for IE6, IE5
        xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
    }
        xmlhttp.onreadystatechange=function() {
            if (xmlhttp.readyState==4 && xmlhttp.status==200) {
            document.getElementById("here").innerHTML=xmlhttp.responseText;
            }
        }
  xmlhttp.open("POST","accountcreation.php",true);
  xmlhttp.send();
}