<script type="text/javascript">

function glasaj(){
if (window.XMLHttpRequest){// code for IE7+, Firefox, Chrome, Opera, Safari
http=new XMLHttpRequest();
} else {// code for IE6, IE5
http=new ActiveXObject("Microsoft.XMLHTTP");
}

var url = "php_file.php";
var params = "prvo=Nekitekst&drugo=Imeprezime";
http.open("POST", url, true);

//Saljemo podatke preko POST
http.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
http.setRequestHeader("Content-length", params.length);
http.setRequestHeader("Connection", "close");

http.send(params);
}

</script>
<a onclick="glasaj();">Glasaj</a>