新建一个cyg.php文件哈
<b>简单计算器</b><br> <form method="post" action="cyg.php"> 结果:<input type="text" name="sum" id="sum" size="15"><br> 数字1:<input type="text" name="num1" size="10"><br> 运算符:<select name="sub"> <option value="+">+</option> <option value="-">-</option> <option value="*">*</option> <option value="/">/</option> </select> <br> 数字2:<input type="text" name="num2" size="10"><br> <input type="submit" value="计算"> <input type="reset" value="重置"> </form> <?php if(!empty($_POST['num1'])){ //如果不为空的情况下 $num1 = $_POST['num1'];//获取第一个输出的值 $num2 = $_POST['num2'];//获取第二个输出的值 $sub = $_POST['sub'];//获取是+还是-还是*还是除 $sum=0; switch($sub){ case "+": $sum=$num1+$num2; break; case "-": $sum=$num1-$num2; break; case "*": $sum=$num1*$num2; break; case "/": $sum=$num1/$num2; break; } echo "<script>alert('计算结果为:".$sum."');</script>"; echo "<script>document.getElementById('sum').value='".$sum."'</script>"; } ?>