在表单提交上显示/隐藏元素
问题描述：
hello I am a php beginner and I have the following problem with my code, I need to add 2 numbers and echo the result as a 3rd number (sum) The sum number must not be shown before clicking the submit button, only the input boxes for the 2 numbers, and when the sum is displayed the 2 input boxes must be hidden and only the sum shown
<html>
<body>
<form method="post" id="form1">
First Number:
<input type="text" name="number1" /><br>
Second Number:
<input type="text" name="number2" /><br>
<input type="submit" name="submit" value="Add" >
</form>
<?php
$number1 = $_POST['number1'];
$number2 = $_POST['number2'];
$sum = $number1+$number2;
echo "Sum = ".$sum;
?>
</script>
</body>
</html>
答
You need to check with isset function to understand if the form is submitted or not. Like following,
<body>
<?php if( !isset($_POST['submit'])){ ?>
<form method="post" id="form1">
First Number:
<input type="text" name="number1" /><br>
Second Number:
<input type="text" name="number2" /><br>
<input type="submit" name="submit" value="Add" >
</form>
<?php } ?>
<?php
if(isset($_POST['submit'])){
$number1 = $_POST['number1'];
$number2 = $_POST['number2'];
$sum = $number1+$number2;
echo "Sum = ".$sum;
}
?>
</script>
</body>
</html>