PHP - Inserting multiple rows in a while loop

Im trying to insert multiple rows in a while loop with a form using implode but cannot seem to make it work. Pls help. I want to insert multiple values named "weight". Like values 30,20,15,10,5 and the remaining emp_id and task_id. Forgive me for being a newbie, but please bare with me. Im still learning.

page1.php

$sql = mysql_query("SELECT 
                    task_tbl.task_id,
                    task_tbl.task_name,
                    task_tbl.task_sem,
                    task_tbl.task_yr,
                    task_tbl.post_id,
                    post_tbl.post_id,
                    post_tbl.post_name AS ppost_name
                    FROM 
                    task_tbl 
                    LEFT JOIN 
                    post_tbl
                    ON
                    task_tbl.post_id = post_tbl.post_id 
                    WHERE 
                    task_sem = '$sem' 
                    AND 
                    task_yr = '$yr' 
                    ORDER BY 
                    task_id ASC");

echo '<form action = "upds_peval.php" name = "add" method = "post">';

while($row = mysql_fetch_assoc($sql)){

        echo "<br/>";
        echo "<b>Employee ID No.:</b>"; 
        echo '<input size = "2" type = "text" name = "emp_id'.$id.'" value = "';
        echo $_POST['emp_id'];
        echo '"/>';
        echo "<br/>";   
        echo "<b>Work/Activity ID No.:</b> ";
        echo '<input size = "2" type = "text" name = "task_id'.$row['task_id'].'" value = "';
        echo $row['task_id'];
        echo '"/>';
        echo "<br/>";
        echo "<b>Work/Activity:</b> ";
        echo $row['task_name'];
        echo "<br/>";
        echo "<b>Weight:</b> ";
        echo '<input size = "1" type="text" name="weight" value = ""/>';
        echo "%";
        echo "<br/>";

        }

        echo '<input type="submit" name="submit" value="ADD"/>';
        echo "</form>"; 

the output would be like:

Employee ID No.: 1001 Work/Activity ID No.: 2002 Work/Activity: Supervises Maintenance and Troubleshooting of Computers Weight: [__]%

Employee ID No.: 1001 Work/Activity ID No.: 2003 Work/Activity: Supervises Software Installation and Maintenance Weight: [__]%

Employee ID No.: 1001 Work/Activity ID No.: 2004 Work/Activity: Maintains, Monitors, and Troubleshoots Virtual Terminals Weight: [__]%

|SUBMIT|

page2.php

mysql_connect ("localhost", "root","")  or die (mysql_error());
    mysql_select_db ("emp_db0");

    if(isset($_POST['submit'])){
    $_POST['weight'];


    $vals=implode(",",$_POST);  

    error_reporting(E_ALL ^ E_NOTICE);

    mysql_query("INSERT INTO peval_tbl(weight,task_id,emp_id) VALUES('$vals')");
    echo "<br/>";
    echo "You have successfully added work/activities!";
    echo "<br/>";   
    }