HTML表格代碼如何改變邊框粗細？

1、事先定義<tableborder="2"><tablestyle="border:2pxsolidred;"><tablestyle="border-bottom:2pxsolidred;">2、通過javascript動態設置<tableid="tab1"><scriptlanguage="javascript"type="text/javascript">varobj;obj=document.getElementById("tab1");obj.style.border="2pxsolidred";</script>