Javascript to update and bind on Parent page

I am creating a child page with an advanced query option that will have over 100 fields to query on. I wanted to dynamically create the query on that child page as a string then send back to the parent web page. I can get the string to the parent ok but I can't seem to get the parent page to invoke any method after it gets the string from the child. I have to Click on the Advanced Query button, create a query, then click on the advanced query button again, then the GridViews all Bind. Any ideas appreciated.
I have a textbox on the parent called mytext. It is AutoPostBack="True". I wastrying to use textchange event that isn't working.
<script lang="javascript" type="text/javascript">     function SendValueToParent() {         var myVal = document.getElementById("mytext").value;         window.opener.form1.mytxt ...