Open html file published by Excel 2007, all line disappear. The border-right-width, border-bottom-width are set to 0.5pt in these html files. In IE8, FF3.6.2, Opera10.5, they are all rounded to 1px. In Safari 4.0.5, Chrome 5.0.342.5, Arora 1.0, they are rounded to 0px.