I added a form element to a page via AJAX and cannot retrive the input value

I added a text input using javascript.

I then tried to assess the value of the text input using

document.getElementById('id').value

but I get a javascript error: Object Required.

--A question would be, does the document object recognize the input element that was added?

Port

i do sort of the same thing with a selection box like this

var myVar=document.areas.namelist.value;

areas is the form name, namelist is the name of the selection box.