I am using a selectbox to display the list of enterpirses from the database. But the onchange event is not triggering. But when i manually once put the value of querystring then it starts working. I dont understand why it is happening.

I am new to javascript and php, kindly suggest me the solution to this.

<select id=enterprisebox onchange=javascript:valueselect() >

    <option value=->-</option>



    <?php foreach($enterprise as $val) { ?>

    <option value=<?php echo $val['customer_id'];?>><?php echo $val['customer_name']?>

    </option>

    <? } ?>



</select>

and my javascript is--

function valueselect()

{

    var i = document.getElementById('enterprisebox');

    var p = i.options[i.selectedIndex].value;

    //alert(p);

    window.location.href = channelinformation.html?selected=+p;

}