Du bør kunne tilrette dette:
<?php
//http://www.eksperten.dk/spm/818759
if(isset($_POST['username'])){
if($_POST['username'] == 'jakobdo')
echo 'Brugernavnet er optaget';
exit();
}
header("Content-Type: text/html; charset=utf-8");
?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "
http://www.w3.org/TR/xhtml1/DTD/strict.dtd"><html>
<head>
<title>818759</title>
<script type="text/JavaScript">
//<![CDATA[
(function(){if(window.XMLHttpRequest)return;var o=null,s,a=["MSXML2.XMLHTTP.5.0","MSXML2.XMLHTTP.4.0","MSXML2.XMLHTTP.3.0","Msxml2.XMLHTTP","Microsoft.XMLHTTP"];for(var i=0,j=a.length;i<j;s=a[i],i++){try{if(o=new ActiveXObject(s))break}catch(e){}}window.XMLHttpRequest=o?function(){return new ActiveXObject(s)}:null;o=null})()
function AjaxReq(sMethod, sUrl, oVars, fnCallBack) {
var oHttp = new XMLHttpRequest();
oHttp.open(sMethod, sUrl, true);
oHttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded; charset=utf-8");
oHttp.onreadystatechange = _fnCallBack;
var aQuery = [];
for (var x in oVars) aQuery.push( encodeURIComponent(x) + "=" + encodeURIComponent(oVars[x]) );
oHttp.send( aQuery.join("&") );
aQuery = null;
function _fnCallBack() {
if (oHttp.readyState<4) return;
fnCallBack(oHttp);
oHttp = null;
}
return this;
}
function myCallBack(oHttp) {
document.getElementById("latest").firstChild.nodeValue = oHttp.responseText;
}
function checkUsername() {
var username = document.getElementById("username").value;
new AjaxReq("POST", "
http://www.codebreaker.dk/exp/818759exp.php", {"username":username}, myCallBack);
}
//]]>
</script>
</head>
<body>
<div>Brugernavn: <input type="text" id="username" /></div>
<div><button onclick="checkUsername()">Tjek</button></div>
<div id="latest"> </div>
</body>
</html>
