Getting Form Values

I need another set of eyes on this. I can't see what I'm doing wrong here:
Code:
<TR>
<TD width=100><P class = "query">First name:</P>
<TD width=75><INPUT size=20 name='FirstName' />
<TR>
<TD width=100><P class = "query">Address:</P>
<TD width=75 colspan="3"><INPUT size=40 name='AddLine1' />
<TR>
<TD width=100><P class = "query"></P>
<TD width=75><INPUT size=40 name='AddLine2' />
<TR>
<TD width=104><P class = "query">City, State, Zip</P>
<TD><INPUT size=30 name='City'>
When the code below gets hold of the form above it sees the AddLine1 and AddLine2 values and returns undefined for FirstName, LastName, and City.

Code:
var theForm = document.memPage;
var FirstName = theForm.FirstName.value;
var LastName = theForm.LastName.value;
var AddLine1 = theForm.AddLine1.value;
var AddLine2 = theForm.AddLine2.value;
var City = theForm.City.value;

Can anyone here tell me what I'm doing wrong?