haciendo esto funciona 
   
Código HTML:
Ver original- <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 
-  <html xmlns="http://www.w3.org/1999/xhtml"> 
-  <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" /> 
-  var mipopup; 
-  function popup(){ 
-  mipopup= window.open("popup.html","PRUEBA","width=700, height=180,menubar=si"); 
-  mipopup.focus(); 
-  } 
-   
-  <form id="neo" name="neo" method="post" action="#"> 
-  <table width="200" border="1"> 
-  <td><input type="text" name="nom" id="nom" /></td> 
-  <input type="button" name="Submit" value="Enviar" onclick="popup()" /> 
popup.html     
Código HTML:
Ver original- <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 
-  <html xmlns="http://www.w3.org/1999/xhtml"> 
-  <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" /> 
-  function datos(nom){ 
-  opener.document.neo.nom.value=nom; 
-  //window.close(); 
-  } 
-   
-  <form id="form1" name="form1" method="post" action="#"> 
-  <table width="200" border="1"> 
-  <td><input type="text" name="nom" id="nom" value="carlos" /></td> 
-  <td><!--<input type="text" name="textfield2" />--></td> 
-  <td><!--<input type="text" name="textfield3" />--></td> 
-   
-  <input type="button" name="S" id="S" value="Enviar" onclick="datos('carlos');" />