Pass Textbox Value To Php Without Submitting Form?

I want to get the value of a textbox into php without clicking the submit button. Here is what I have My form field:

#1
<input type="text" style=background:transparent; border:0px; name='clientid' >

This field is populated dynamically by its name with another php script in this way
#2

echo "formObj.clientid.value = '".toSafeString($inf["clientID"])."';
";

Now I want to take the value in code#1 (name='clientid') and pass it to a php code that is in the same file as the form. Here is the php code

<?php
$name=$_POST['name'];//this is where the value of the text box mentioned is defined
include 'datalogin.php';

[Code]....

I know this may require js