Having trouble sending a form to a window.

I'm a bit stymied on what I'm doing wrong. I have the following apparently straightforward HTML code:

<form name="editForm" method="post" action="updPurchDataEdit.jsp" target="PurchEdit">
<input type="hidden" name="purchaseId" value="168">
</form>

<div style="position: absolute; top: 110px; left: 60px; font-size: smaller; font-weight: bold"
  onmouseover="document.body.style.cursor='pointer';"
  onmouseout="document.body.style.cursor='auto';"
  onclick="location='updPurchDataEdit.jsp?purchaseId=168'"

<!--  onclick="var w = window.open('','PurchEdit','width=900,height=540,top=50');
    w.focus();
    document.editForm.submit();"-->

<img alt="" style="vertical-align: bottom" src="images/Write1a.gif"/> Edit Purchase
</div>

Select allOpen in new window

When I run this as shown, it works fine. When I run the commented code ("var w = ...) instead of the "location= ..." code, I get a blank page, no form inside. I've done this dozens of times and in fact have another such window.open in the same program that works fine. Can anyone see what might be wrong here? This used to work.