Creating A Form Script That Validate And Fill Some Inputs?

i'm creating a form script that use javascript to validate and fill some inputs

form.php

HTML Code:

<script type="text/javascript" src="./javascript/validate.js"></script>
<form class="create" action="#" method="POST" name="form1" id="form1" onSubmit="return validate();">
<fieldset>

[code]....

now the inpName[0] works but i can't find out how i van do the same for inpName[1] and later inpName[2] inpName[3] inpName[4] inpName[5].

i can only find a wat by copy the full document.getElementById(inpName[0]).xxx but i loke a small clean that everyone understand.