การทำ Dropdown แล้วแสดงภาพให้ขึ้น ด้วย Javascript อย่างง่าย

echo"<form name=\"frmaddsub\" method=\"post\" action=\"\" onclick=\"return chkSub();\">";
		?>
			<script language="JavaScript">
			function showimg(PID){
			var test1=document.frmaddsub.kindtype;
			if(test1.value!=""){

				<?$strSQL = "SELECT PPicture FROM stock_tb_product where PID='PID'";
				$objQuery = mysql_query($strSQL);
				$objResult = mysql_fetch_array($objQuery);?>
				strGroup = <?=$objResult["PPicture"];?>;

				document.frmaddsub.imgAvatar.src="image/product/strGroup";
			}
			}
			</script>
			<?echo"<table width=\"600\" border=\"0\" style=\"border:1px solid;background:#FFFFFF;\">";
			echo"<tr>";
			echo"<td width=\"140\">สินค้า</td>";
			echo"<td><select name=\"kindtype\" id=\"kindtype\" style=\"width:82%;\" OnChange=\"showimg(this.value);\"><option value=\"\">โปรดเลือกรายการ</option>";
			$sql="Select * from stock_tb_product order by PID";
			mysql_query("SET NAMES utf8");
			$rs=mysql_query($sql);
			while($row=mysql_fetch_array($rs)){
				echo"<option value=\"".$row['PID']."\">".$row['PNameThai']."</option>";
			}
			echo"</select></td>";
			echo"<td rowspan=\"10\" width=\"130\" height=\"130\" valign=\"middle\" align=\"center\"><img id=\"imgAvatar\" width=\"96\" height=\"96\"></td>";
			echo"</tr>";
			echo"<tr>";
			echo"<td>Serial Number</td>";
			echo"<td><input type=\"text\" name=\"serialno\" id=\"serialno\" autocomplete=\"off\" style=\"width:80%;\" /></td>";
			echo"</tr>";