php实现的简单美国商品税计算函数

<?php function tax($total,$tax_amount){   $tax_rate = $tax_amount * .01;   $tax = $total * $tax_rate;   return $value = $tax + $total; } $price = 50.00; //In U.S. Dollars $taxrate = 6.5; //In percentage echo "$".tax($price,$taxrate); ?>