让我们再进一步了解PHP流程控制语句之if语句吧！！！(附源码)

<form action='' method='get'>
     <input type="text" name="num1">
     <select name="fh">
        <option value="jia">+</option>
        <option value="jian">-</option>
        <option value="c">*</option>
        <option value="chu">/</option>
        <option value="qy">%</option>
      </select>
      <input type="text" name="num2">
      <input type="submit" value="运算"/> 
</form>

<?php
     $num1 = $_GET['num1'];
     $num2 = $_GET['num2'];
     $fh =$_GET['fh'];

     if(!is_numeric($num1) || !is_numeric
          ($num2)){
              echo '请输入数值类型';
          }
          if($fh=='jia'){
              echo $num1 . '+' . $num2 . '=' .
              ($num1+$num2);
          }
          if($fh=='jian'){
            echo $num1 . '-' . $num2 . '=' .
            ($num1-$num2);
        }
        if($fh=='c'){
            echo $num1 . '*' . $num2 . '=' .
            ($num1*$num2);
        }
        if($fh=='chu'){
            echo $num1 . '/' . $num2 . '=' .
            ($num1/$num2);
        }
        if($fh=='qy'){
            echo $num1 . '%' . $num2 . '=' .
            ($num1%$num2);
        }




?>