เปลี่ยนจาก Checklist เป็น Button เมื่อคลิกแล้วให้นับจำนวนคลิก เมื่อคลิกซ้ำให้ลบ php+Mysql

<script type="text/javascript">
	// count
	Array.prototype.count = function(){
		var cnt = 0;
		for (i =0;i<this.length; i++) {
			if(this[i]!=0){cnt++;}}
		return cnt;
		}
		
	function getVal(){
		var el=document.getElementById('McNo');
		var i=0, c, arr=[];
		while(c=document.getElementById('mc'+(i++))) c.checked? arr[arr.length]=c.value : null;
		el.value = arr.join(", ");
		document.getElementById('mCount').value=arr.count();
		mc=document.getElementById('mCount').value;
		mb = document.getElementById('mcTotal').value;
		mTotal = Number(mb)-Number(mc);
		document.getElementById('mcBal').value=mTotal;
	}
</script>

  <tr>
<? $i=0;do { ?>
    <td width="150px">
    <input name="mc[]" type="checkbox" class="checkbox" id="<? echo "mc".$i;?>"  title="<? echo $row_rsTW1['Mc']; ?>" onclick="getVal()" value="<? echo $row_rsTW1['Mc'];?>">
		 	<span style="font-size:45px;"><? echo str_pad($row_rsTW1['Mc'],2)?></span></br>
			<div align="center"><span class="font_mc"><? echo $row_rsTW1['McName'] ?></span><span class="font_mc"><? echo " ".$row_rsTW1['Spindle']." D"; ?></span></div>
    </td>
	<? if($a>=9){?> </tr> <? $a=-1;}?>
	<? $a++;$i++;
	}while($row_rsTW1 = mysql_fetch_assoc($rsTW1));?>
    </tr>