<script language="javascript">
function check(){
if(!document.getElementById("a").checked){//没有选中
document.getElementById('submit').style.backgroundColor="#666666"
document.getElementById('submit').style.borderColor="#333333"
document.getElementById('submit').style.color="#000000"
document.getElementById('submit').disabled="disabled";
}else{//选中
document.getElementById('submit').disabled="";
document.getElementById('submit').style.backgroundColor="#0033FF"
document.getElementById('submit').style.borderColor="#0066FF"
document.getElementById('submit').style.color="#ffffff"
}
}
</script><form name="f">
<INPUT TYPE="checkbox" id="a" onclick="check()" checked="checked">
<INPUT TYPE="submit" VALUE="注册" id="submit">
</form>
function check(){
if(!document.getElementById("a").checked){//没有选中
document.getElementById('submit').style.backgroundColor="#666666"
document.getElementById('submit').style.borderColor="#333333"
document.getElementById('submit').style.color="#000000"
document.getElementById('submit').disabled="disabled";
}else{//选中
document.getElementById('submit').disabled="";
document.getElementById('submit').style.backgroundColor="#0033FF"
document.getElementById('submit').style.borderColor="#0066FF"
document.getElementById('submit').style.color="#ffffff"
}
}
</script><form name="f">
<INPUT TYPE="checkbox" id="a" onclick="check()" checked="checked">
<INPUT TYPE="submit" VALUE="注册" id="submit">
</form>
document.getElementById("submit").style.属性='值';按照你的需求自己设置吧