Javascript - copying form values across windows

[Mister_Pister]

Lets say I have a form called editform and a field called coords in it.

What I need to do is launch a popup window which does something and grabs some values in its own form field. Then the user clicks an add button to copy the value over to the coords box in the original window - how can I do this?

 

[GravyMonster]

all you need is first some javascript to open a window, google is your friend

Then to get at the elements of the parent window you just need
opener.frmParentForm.elElement.value = document.frmThisForm.elElement.value
then window.close() to close the child.

Job done