<script type="text/javascript" src="Testing_Ajax.js"></script>
<script type="text/javascript" src="jquery-1.5.js"></script>

<script type="text/javascript">
    $(document).ready(function(){
        $("div").addClass('cls_display');
        $("input.cls_post").click(function(){
            $.post("Display_Ajax.php",{username: "john", password: "abcd"});
        });
    });
</script>
<style>
    .cls_display{
        background-color: green;
    }
</style>

<form name="nm_form" method="POST" action="Display_Ajax.php">
    <table>
        <tr><td>User Name:</td><td><input type="text" name="nm_username" id="id_username"/></td></tr>
        <tr><td>Password:</td><td><input type="text" name="nm_password" id="id_password"/></td></tr>
        <tr><td><input type="button" value="Submit" onclick="runAjax()"/></td></tr>
        <tr><td><input type="button" class="cls_post" value="Submitforajax"/></td></tr>
    </table>
    <div id="id_display" class="cls_display">

    </div>
</form>