·如何通过 document.getElementById(ID) 获得控件的背景颜色值？
function ck(id)
{
document.getElementById(id).style.backgroundColor;//大概意思，但这样不对
}
</script>

－－－－－－

<table width= "80% " border= "1 ">
<tr id= "tr1 " bgcolor= "#ff0000 ">
<td colspan= "3 ">
<input type= "checkbox " name= "checkbox " value= "1 " onclick= "ck( 'tr1 ') " />
</td>
</tr>
</table>

------解决方案--------------------
try

document.getElementById( "tr1 ").style.backgroundColor = "red ";