麻烦找找错！！！

[lemonhuang]

function checkthis(a)
{
if (!a.checked)
{
div1.style="display:none"
}
else
{
div1.style=''
}
}

[meizz]

function checkthis(a){
if (!a.checked){div1.style.display = "none";}
else {div1.style.display = "block";}
}

[qiushuiwuhen]

function checkthis(a){div1.style.display = (a.checked?"block":"none");}

[chenzengxi]

来晚了，哎~~~~~~~~~~

[sjsky]

function checkthis(a)
{
if (!a.checked)
{
div1.style.display="none"
}
else
{
div1.style=""}
}

[saucer]

function checkthis(a)
{
if (!a.checked)
{
div1.style.display = "none";
}
else
{
div1.style.display ='';
}
}

[JK_10000]

好象是div1.style的类型不是String，而是其它的什么Object,所以不能赋给字符串值