Foros del web, para los que viven de bits

<script>
var request = false;

if (window.XMLHttpRequest) {
	request = new XMLHttpRequest();
}

function checkName(nick,clave) {

	if (window.ActiveXObject) {
    	try {
            request = new ActiveXObject("Msxml2.XMLHTTP");
        } catch(e) {
            try {
                request = new ActiveXObject("Microsoft.XMLHTTP");
            } catch(e) {
                request = false;
            }
        }
    }

    if (request) {
        request.onreadystatechange = processReqChange;
        request.open("GET", "check.php?nk="+nick+"&cl="+clave);
        request.send(null);
    }
}

function processReqChange() {
    var result = document.getElementById("result");

    if (request.readyState == 4) {
        if (request.status == 200) {
            result.innerHTML = request.responseText;
        }
    } else {
        result.innerHTML = "Espere, procesando los datos ...";
    }
}
</script>
<style type="text/css">
<!--
.result {
	background-color: #BBFBBD;
	border: 1px solid #006600;
}
-->
</style>

<form name="form1" method="post" action="" onSubmit="checkName(form1.ni.value,form1.cl.value)">
  Nick:<br>
  <input name="ni" type="text" id="ni">
  <br>
  Clave:<br>
  <input name="cl" type="text" id="cl">
  <br>
  <input type="submit" name="Submit" value="Entrar">
</form>
<div class="result" id="result"></div>