http://www.quirksmode.org/bugreports/archives/safari/index.html "When you remove the elements of a form, Safari nonetheless keeps references to these removed elements in the document.forms.elements array. Test page. http://pixy.cz/temp/test/safari_js_bug/index.html Workaround is not included. Reported by Petr Stanicek."
Fixed in latest nightly, closing as worksforme.