请帮忙给我写下面表格在HTML5中用JS代码计算小计和总金额的程序代码！谢谢了！急急急急急急！！！！！！

    
        Order Details
        
            Product Code
            Decription
            Qty
            Price
            Total
        
        
            COMP001
            The Ultimate Smartphone        
            
            $399.99
            $0.00
        
        
            COMP002
            The Ultimate Tablet        
            
            $299.99
            $0.00
        
        
            COMP003
            The Ultimate Netbook        
            
            $499.99
            $0.00
        
        
            Order Total
            $0.00