<input type="button" id="tianjia" value="保 存" class="btn1" onClick="nullCheck(this)"/>
<script>
function nullCheck(obj)
{
......//這里寫你所需功能的代碼
}
</script>

<input type="checkbox" name='agentType' id="exclusiveAgenter" value="exclusive" onchange="clickAgenter(this)">

function clickAgenter(obj){
if($(obj).attr("checked")=="checked"){
$("[name='agentType']").removeAttr("checked");//取消全選
$(obj).attr("checked","checked")
}
}