javascript sum ราคารวมทั้งหมดมันไม่บวกให้อัติโนมัติค่ะ......

</head> 
<form action="save_estchkmotor.php" method="post" > 
<div data-role="page">

    <div class="tab-content">
        <div class="tab2">

        <table>
        <tr align="center">
           <td width="3%">#</td>
           <td width="27%">รายการอะไหล่</td>
           <td width="26%">เบิก/ทำสี</td>
           <td width="18%">ราคา</td>
           <td width="13%">จำนวน</td>
           <td width="13%">ราคารวม</td>
        </tr>
		<?
           include "connect.php";
		   $strSQL   = "SELECT * FROM spares_estimate
                         WHERE			 
                         brand_id   = '".$_GET["bID"]."'  AND
                         class_id   = '".$_GET["cID"]."'  AND
                         group_no 	= '1' 		ORDER BY sp_name ASC";
            $objQuery = mysql_query($strSQL) or die ("Error Query [".$strSQL."]");
			$count    = mysql_num_rows($objQuery);
			$x=0;
            while($objResult = mysql_fetch_array($objQuery))
            {
                $x++;
				$sp_code   = $objResult["sp_code"];
				$sp_name   = $objResult["sp_name"];
				$price     = $objResult["price"];
				$brand     = $objResult["brand_id"];
				$class     = $objResult["class_id"];
        ?>
        <tr align="center">
           <td width="3%" align="left"><b><?=$x;?></b></td>
           <td width="27%" align="left"><?=$sp_name;?></td>
           <input name="sp_name[<?=$x;?>]" type="hidden" value="<?=$sp_name;?>" />
           <input name="sp_code[<?=$x;?>]" type="hidden" value="<?=$sp_code;?>" />
           <input name="strno" type="hidden" value="<?=$_GET["mID"];?>" />
           <input name="brand" type="hidden" value="<?=$brand;?>" />
           <input name="class" type="hidden" value="<?=$class;?>" />
          
           <td width="26%">
               <input type="checkbox" name="chk_take[<?=$x;?>]" id="chk_take<?=$x;?>_1" value="1"/>
               <label for="chk_take<?=$x;?>_1" >เบิก</label>
               <input type="checkbox" name="chk_take[<?=$x;?>]" id="chk_take<?=$x;?>_2" value="2" />
               <label for="chk_take<?=$x;?>_2">ทำสี</label>
               </td>
           <td width="18%"><?=$price;?></td>
            <input name="price<?=$x;?>" id="price<?=$x;?>" type="hidden" type="text" value="<?=$price;?>" />
            
           <td width="13%">
               <input type="text" name="take<?=$x;?>" id="take<?=$x;?>" autocomplete="off" 
               onKeyDown=" if(this.value==0) this.value = '';"  
               onKeyUp="if(this.value==0) this.value=0;
               document.all.total<?=$x;?>.value = parseFloat(document.all.take<?=$x;?>.value)* <?=$price;?>;
               
               if(document.getElementById('sum').value == '')document.getElementById('sum').value = 0;
               document.getElementById('sum').value = parseFloat(document.getElementById('sum').value)+parseFloat(document.all.total<?=$x;?>.value);" value="0">
           </td>
           <td width="13%"><input type="text" name="total<?=$x;?>" id="total<?=$x;?>">
           </td>
        </tr>
		<? } ?>
        <tr style="color:#F00;">
            <td colspan="4" align="center"> ราคารวม(บาท)</td>
            <td colspan="2"> 
               <input type="text" name="sum" id="sum" >
            </td>
        </tr>
        <tr>
        	<input name="count" type="hidden"  value="<?=$x;?>">
            <td colspan="6" align="center">
            <input type="submit" value="บันทึก"  data-role="button" data-inline="true" data-theme="b"></td>
        </tr>	
        </table>
        </div>
    </div>
</div>
</form>