calculate amount

[Nana_Osei]

I am trying to multiply the price with quantity and insert it into amount text field without doing a post. Is there a way if I enter quantity the amount would show?

$rs = mysql_query("SELECT * FROM contributions where type = 'ticket'");

    // create an array holding the classes you want to switch between
$classes=array("td1","td2");
    // a counter to keep track of which class is currently being used
$classifier=0;
$num = mysql_num_rows($rs);
$i = 0;

echo "<TABLE  width=100% align=left cellpadding=5 cellspacing=0>";
echo "<tr class=trhead >";

echo"<td>Description</td>";
echo"<td>Price</td>";
echo"<td>Quantity</td>";
echo"<td>Amount</td>";
echo "</tr>";

while ($i < $num){
$description = mysql_result($rs,$i,"description");
$price= mysql_result($rs,$i,"price");


//$dmiddle= mysql_result($rs,$i,"middle");

// access the value in the array associated with the key equal to the counter and print it in the <tr> bg
echo "<tr class=" . $classes[$classifier] .">";
echo "<td>" . $description .  "</td>";
echo "<td>" ."$". $price . "</td>";
echo '<td><input type="text" name="quantity[]" value="" size="1" /></td>';
$myamount = $price * $_GET[quantity]; 
echo '<td ><input type="text" name="amount[]" value="" size="3" /></td>';

$i++;
    // increment the counter and mod it by 2 to effectively alternate between two numbers
$classifier=($classifier+1)%2;
 }

}
echo "</table>";
?>

[ixalmida]

First, you're asking a JavaScript question, so this is probably the wrong forum. You'll also have to add a hidden field you can use for your calculation (assuming you don't want the price to change).

Second (and this is just my imho), you're writing WAAAAAYYY too much code for what should be a simple query & array extract procedure.

Try this:

// create an array holding the classes you want to switch between
$classes=array("td1","td2");

// a counter to keep track of which class is currently being used
$classifier=0;

echo "<TABLE width=100% align=left cellpadding=5 cellspacing=0>";
echo "<tr class=trhead >";

echo"<td>Description</td>";
echo"<td>Price</td>";
echo"<td>Quantity</td>";
echo"<td>Amount</td>";
echo "</tr>";

// Get recordset (moved this down, just to keep stuff together)...
$rs = mysql_query("SELECT * FROM contributions where type = 'ticket'");

// Create your form...
echo "<form name='myform' action='some_other_page.php' method='post'";

// Loop through each row of recordset...
while ($row = mysql_fetch_array($rs))
  {
  // Extract recordset fields into local variables with the same names...
  extract($row);

  // access the value in the array associated with the key equal to the counter and print it in the <tr> bg
  echo "<tr class=" . $classes[$classifier] .">";
  echo "<td>" . $description . "</td>";
  echo "<td>" ."$". $price . "</td>";
  echo '<input type="hidden" name="price" value="'.$price.'">';
  echo '<td><input type="text" name="quantity[]" value="" size="1" /></td>';
  echo '<td ><input type="text" name="amount[]" value="" size="3" /></td>';

  // increment the counter and mod it by 2 to effectively alternate between two numbers
  $classifier=($classifier+1)%2;
  }
echo "<input type='button' name='update_amount' onclick='do some JavaScript to calculate the new amount value and display it;'>"
echo "</form>";
echo "</table>";