Hi,<BR><BR>I currently have a web user control (pf_imageselector.ascx) which is dynamically created (any number of times) on a parent web user control (pf_fillitems.ascx) which in turn has been loaded into a webform (default.aspx). On the user control is a text box called txbSelectedImage and a button. On click of the button run&#039;s this code:<BR><BR>function OpenChild()<BR>{<BR> <BR>var strImageFile;<BR>var WinSettings = "height=580,width=630,status=yes,toolbar=no,menuba r=no,location=no";<BR><BR>window.open("pf_stockima ge.aspx", null, WinSettings);<BR><BR>}<BR><BR>Which obviously open a child webform. From here the user can select something from a listbox and the click another button, which then hopefully passes back the selected value to the textbox on the parent user control. Code so far is:<BR><BR>function PassSelectedImage()<BR>{<BR><BR>var lstImages = document.forms[0].lstImages;<BR>var i = lstImages.selectedIndex;<BR><BR>window.opener.docu ment.forms[0].txbSelectedImage.value = lstImages.options[i].value;<BR>window.close();<BR><BR>}<BR><BR>My problem is that I get an erorr stating that above is null or not an object. How do I reference the textbox that is sitting inside the user control (ID is generated at runtime), which is also sittting in another usercontrol (I know the ID of this one) on a webform (default.aspx, which as a form called Form1).