您如何将php函数放在php echo内的html表单中？

Question

I am trying to make a paypal checkout button, the button works fine when it is not inside of an echo, but when I put the button inside of an echo because I need it to dynamically be produced, it has a problem referencing the "paypal_items();" function, which is what adds all of the items that a user has in their cart. The button works, it redirects to the paypal website but it says there are no items (which makes me believe that the paypal_items() isn't getting reached. I've tried a bunch of different syntaxes but I can't figure anything out and I'm wondering if this is even possible because it's inside a form which is furthermore inside of an echo.

There is a lot more that happens in cart(), I just erased most of it because it seemed unnecessary, it basically gathers the session data for what is in the cart and then echo's it for the buyer to see.

function paypal_items() { //this function takes the cart and organizes all the variables in a way that paypal can read it (this function is called on in the paypal send form)
$num = 0;
foreach($_SESSION as $name => $value) {
    if ($value!=0) {
        if(substr($name, 0, 5)=='cart_') {
            $id = substr ($name, 5, strlen($name)-5);
            $get = mysql_query ('SELECT id, name, price FROM products WHERE id='.mysql_real_escape_string((int)$id));
            while ($get_row = mysql_fetch_assoc ($get)) {
                $num++;
                echo '<input type="hidden" name="item_number_'.$num.'" value="'.$id.'">'; //This num and number from database listing is flip flopped.
                echo '<input type="hidden" name="item_name_'.$num.'" value="'.$get_row['name'].'">';
                echo '<input type="hidden" name="amount_'.$num.'" value="'.$get_row['price'].'">';
                echo '<input type="hidden" name="shipping_'.$num.'" value="'.$get_row['shipping'].'">'; //Cost of Shipping first item.
                echo '<input type="hidden" name="shipping2_'.$num.'" value="'.$get_row['shipping'].'">'; //Cost of shipping two or more items is applied (shipping is multiplied depending on quantity)
                echo '<input type="hidden" name="quantity_'.$num.'" value="'.$value.'">';
            }
        }
    }
} 

}

function cart() {
    if ($total = 0) {
           // Empty Cart Alert..
    }

    else {
        echo '<div class="checkoutBtn">'.'<p>
              <form action="https://www.paypal.com/cgi-bin/webscr" method="post">
                 <input type="hidden" name="cmd" value="_cart">
                 <input type="hidden" name="upload" value="1">
                 <input type="hidden" name="business" value="blah@blahblah.com">
                 <?php paypal_items(); ?>
                 <input type="hidden" name="currency_code" value="USD">
                 <input type="hidden" name="amount" value="echo number_format($total, 2);">
                 <input type="image" src="images/cartPage/checkoutBtn.gif" width="247" height="54" name="submit" alt="Secure Checkout With PayPal!">
              </form>
            </p>;'.'</div>'.
    }
}

Answer 1

Try it this way:

function cart() {
    if ($total = 0) {
           // Empty Cart Alert..
    }

    else {
        echo '<div class="checkoutBtn"><p>
              <form action="https://www.paypal.com/cgi-bin/webscr" method="post">
                 <input type="hidden" name="cmd" value="_cart">
                 <input type="hidden" name="upload" value="1">
                 <input type="hidden" name="business" value="blah@blahblah.com">';
        paypal_items();
        echo '<input type="hidden" name="currency_code" value="USD">
                 <input type="hidden" name="amount" value="'.number_format($total, 2).'">
                 <input type="image" src="images/cartPage/checkoutBtn.gif" width="247" height="54" name="submit" alt="Secure Checkout With PayPal!">
              </form>
            </p></div>';
    }
}

Answer 2

Euhm the <?php tags are on the wrong place.

Try this:

     <?php
    function cart() {
if ($total = 0) {
          // Empty Cart Alert..
  }
else {
    echo '<div class="checkoutBtn">'.'<p>
          <form action="https://www.paypal.com/cgi-bin/webscr" method="post">
             <input type="hidden" name="cmd" value="_cart">
             <input type="hidden" name="upload" value="1">
             <input type="hidden" name="business" value="blah@blahblah.com">
              paypal_items();
             <input type="hidden" name="currency_code" value="USD">
             <input type="hidden" name="amount" value="echo number_format($total, 2);">
             <input type="image" src="images/cartPage/checkoutBtn.gif" width="247" height="54" name="submit" alt="Secure Checkout With PayPal!">
          </form>
        </p>;'.'</div>'.
   }
}
?>