javascript values into server side textboxes ..Please help!

Hey
I would like to know if someone can please be so kind to help me with this javascript ..Please......
I have 5 values that goes to html labels......but how can I change the javascript so that I get all 5 values in a 5 server side textboxes instead of a htm labels.

here my code

<script type="text/javascript">

    function showInfoWindow(point) {
        var index;
        var title;
        var marker;
        var newZoom = GoogleMap1.GMap.getZoom();
        for (index in GoogleMap1.Markers) {
            marker = GoogleMap1.Markers[index];
            if (marker.Latitude = ...