Javascript usage during ajax code
===

I'm renewing question. For simplify situation I've this script in **index.php** file

    <form name="f" action="index.php" method="post">
        <input type="button" name="but" id="but" value="Retrieve">
        <div id="div"></div>
        <input type="submit" name="ok">
    </form>
    
    
    
    <script type="text/javascript">
    document.getElementById("but").onclick = function(){
        var http = false;
        if (window.XMLHttpRequest){
            http = new XMLHttpRequest();
        } else {
            http = new ActiveXObject("Microsoft.XMLHttp");
        }
        if (http){
            http.open("POST","other.php",true);
            http.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
            http.onreadystatechange = function(){
                if (http.status==200 && http.readyState==4){
                    document.getElementById("div").innerHTML = http.responseText;
                }
            };
            http.send(null);
        }
    };
    document.getElementById("y").onclick = function(){
        alert("okaaay");
    };
    </script>

And have **other.php** file with the script below

    <?php
    echo "<input type='text' name='y' id='y'>";
    ?>

Ajax script works just nice, but my problem is that when this marked input element is retrieved in index.php page , with second JavaScript code I can't manipulate it , please help , thanks :)