";        if($_POST['num1']==""){            $bz = false;            $errs .= "第一个数为空 
";        }        if($_POST['num2']==""){            $bz = false;            $errs .= "第二个数为空 
";        }        if($bz){            $sum = "";            switch($_POST['ysf']){                case '+':                    $sum = $_POST['num1'] + $_POST['num2']; break;                case '-':                    $sum = $_POST['num1'] - $_POST['num2']; break;                case '*':                    $sum = $_POST['num1'] * $_POST['num2']; break;                case '/':                    $sum = $_POST['num1'] / $_POST['num2']; break;            }        }    }?>                            
     
                  
                      
       
easy calculator
      
                      
       
                            
                         
                    
                            
                                                    
            value="+">+                            
            value="-">-                            
            value="*">*                            
            value="/">/                                            
                            
                         
                    
                            
                         
                    
                       
       
                       
       
                            
                        
         ";                            }                            else{                                echo $errs;                            }                        ?>