Passing data between windows (help pls...)

I have this button that opens a pop up window:


function openAssetSelector(fieldname) {
window.open( "connector.php", fieldname, "height = 600, width = 700" )
}


<?php

echo("<input name='SectionBanner_file' type='text' />

<input onclick=\"openAssetSelector('SectionBanner_file')\";' type='button' value='Browse Server' >");

?>

When clicking on browse server button, a pop up window will open and a link is on the page. When clicking on the link, the parent window's text field box will be filled with the link text:

var fieldname = window.top.name;
window.top.opener.edit.fieldname.value = linktext;

but I have problem as it says window.top.opener.edit has no properties.

Can someone help me out? Thanks!