JavaScript POST and GET request

POST and GET request

<script language="javascript">
function createXMLHttpRequest() {
    if (window.ActiveXObject) {
        xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
    }
    else if (window.XMLHttpRequest) {
        xmlHttp = new XMLHttpRequest();
    }
}
function GETRequest(query) {
    createXMLHttpRequest();
    var queryString = "index.php?" + query;
    xmlHttp.onreadystatechange = handleStateChange;
    xmlHttp.open("GET", queryString, true);
    xmlHttp.send(null);
}
function POSTRequest(query) {
    createXMLHttpRequest();
    var url = "index.php";
    xmlHttp.open("POST", url, true);
    xmlHttp.onreadystatechange = handleStateChange;
    xmlHttp.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");    
    xmlHttp.send(query);
}
function handleStateChange() {
    if(xmlHttp.readyState == 4) {
        if(xmlHttp.status == 200) {
            parseResults();
        }
    }
}
function parseResults() {
     alert(xmlHttp.responseText);
    // document.getElementbyId('index').innerHTML = xmlHttp.responseText;
}

</script>

<?php
foreach ($_REQUEST as $variablename => $value){
	echo $variablename.' = '.$value;
	echo "\n <br>";
}
?>