将数据插入数据库后清除文本字段

Question

我编写了 php 代码来将记录插入 MySQL 数据库。数据插入成功。所以，我想在插入数据库后清除文本字段记录。这是我的代码。

<div class="form">
<h1>Application Form</h1>
<p><span class="error">* required field.</span></p>
<form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">
<pre><div class="app">
First Name          :   <input type="text" size="48"  align="middle" name="firstname" value="<?php echo $firstname;?>">
   <span class="error" style="background-color:#FF0000">* <?php echo $firstnameErr;?></span>
Last Name           :   <input type="text" size="48" align="middle" name="lastname" value="<?php echo $lastname;?>">
   <span class="error"  style="background-color:#FF0000">* <?php echo $lastnameErr;?></span>
Company / Organization      :   <input type="text" size="48" name="company" value="<?php echo $company;?>">
   <span class="error"><?php echo $companyErr;?></span>
Home Page           :   <input type="text" size="48" name="homepage" value="<?php echo $homepage;?>">
   <span class="error"><?php echo $homepageErr;?></span>
Contact No          :   <input type="text" size="48" name="contactno" value="<?php echo $contactno;?>"><span class="error"><?php echo $contactnoErr;?></span> 
Address Line 01         :   <input type="text" size="48" name="addressline1" value="<?php echo $addressline1;?>">
   <span class="error" style="background-color:#FF0000">* <?php echo $addressline1Err;?></span>
Address Line 02         :   <input type="text" size="48" name="addressline2" value="<?php echo $addressline2;?>">
   <span class="error" style="background-color:#FF0000">* <?php echo $addressline2Err;?></span>
City                    :   <input type="text" size="48"  name="city" value="<?php echo $city;?>">
   <span class="error" style="background-color:#FF0000">* <?php echo $cityErr;?></span>
Postal Code             :   <input type="text" size="48"  name="postalcode" value="<?php echo $postalcode;?>">
   <span class="error" style="background-color:#FF0000">* <?php echo $postalcodeErr;?></span>
Country                     :   <input type="text" size="48"  name="country" value="<?php echo $country;?>">
   <span class="error" style="background-color:#FF0000">* <?php echo $countryErr;?></span>
Email                       :   <input type="text" size="48"  name="email" value="<?php echo $email;?>">
   <span class="error" style="background-color:#FF0000">* <?php echo $emailErr;?></span>
Fill the below section if you are submitting abstract only. Otherwise ignore it. <br />
Abstract Details    :      <textarea name="abstractdetails" rows="5" cols="40"><?php echo $abstractdetails;?></textarea>
<p>Click the button to display an alert box:</p>
<button>Save</button>
<input type="reset" name="submit" value="Cancel" align="middle">
<br><br></div>
</form> 
  </table>
<?php
try {
$db_user = 'root';
$db_pass = 'xxxxx';
$db = new PDO( 'mysql:host=localhost;dbname=abc', $db_user, $db_pass );
$form = $_POST;
$sql = "INSERT INTO app ( 
    firstname, lastname, company, homepage, contactno, addressline1, addressline2, city, 
 postalcode, country, email,  abstractdetails ) 
    VALUES ( 
    :firstname, :lastname, :company, :homepage, :contactno, :addressline1, :addressline2, 
:city,   :postalcode, :country, :email, :abstractdetails )";
$query = $db->prepare( $sql );
$query->execute( array( ':firstname'=>$firstname, ':lastname'=>$lastname, 
':company'=>$company, ':homepage'=>$homepage, ':contactno'=>$contactno,
 ':addressline1'=>$addressline1, ':addressline2'=>$addressline2, ':city'=>$city, 
':postalcode'=>$postalcode, ':country'=>$country, ':email'=>$email,
  ':abstractdetails'=>$abstractdetails ));
if($query->rowCount() > 0){
  echo  "Record Inserted Successfully !!"; 
}
}
catch(PDOException $e)
{
echo $e->getMessage();
}
?>

Answer 1

您正在为输入字段 value = "<?php echo $lastname;?>" 指定值，如果您这样做显然表单数据将重新填充。如果您想简单地阻止这种情况，请从所有字段中删除这些属性。

Answer 2

如果您将 PHP 放在页面顶部，您可以在成功时将所有变量重置为空白。

<? php
try {
    $db_user = 'root';
    $db_pass = 'xxxxx';
    $db = new PDO('mysql:host=localhost;dbname=abc', $db_user, $db_pass);
    $form = $_POST;
    $sql = "INSERT INTO app ( 
 firstname, lastname, company, homepage, contactno, addressline1, addressline2, city, postalcode, country, email, abstractdetails) VALUES (:firstname, :lastname, :company, :homepage, :contactno, :addressline1, :addressline2, :city, :postalcode, :country, :email, :abstractdetails)";
    $query = $db - > prepare($sql);
    $query - > execute(array(':firstname' = > $firstname, ':lastname' = > $lastname, ':company' = > $company, ':homepage' = > $homepage, ':contactno' = > $contactno, ':addressline1' = > $addressline1, ':addressline2' = > $addressline2, ':city' = > $city, ':postalcode' = > $postalcode, ':country' = > $country, ':email' = > $email, ':abstractdetails' = > $abstractdetails));
    if ($query - > rowCount() > 0) {
        echo "Record Inserted Successfully !!";
        $firstname = ""; $lastname = ""; // ...
    }
} catch (PDOException $e) {
    echo $e - > getMessage();
} ?>
<div class="form">
    < h1>Application Form
        < /h1>
            <p><span class="error">* required field.</span > < /p> <form method="post" action="<?php echo htmlspecialchars($_SERVER[" PHP_SELF"]);?>"> <pre><div class="app"> First Name : <input type="text" size="48" align="middle" name="firstname" value="<?php echo $firstname;?>"> <span class="error" style="background-color:#FF0000">* <?php echo $firstnameErr;
    ?></span > Last Name: < input type = "text"
    size = "48"
    align = "middle"
    name = "lastname"
    value = "<?php echo $lastname;?>" > < span class = "error"
    style = "background-color:#FF0000" > * <? php echo $lastnameErr; ?> < /span> Company /
    Organization: < input type = "text"
    size = "48"
    name = "company"
    value = "<?php echo $company;?>" > < span class = "error" > <? php echo $companyErr; ?> < /span> Home Page : <input type="text" size="48" name="homepage" value="<?php echo $homepage;?>"> <span class="error"><?php echo $homepageErr;
    ?></span > Contact No: < input type = "text"
    size = "48"
    name = "contactno"
    value = "<?php echo $contactno;?>" > < span class = "error" > <? php echo $contactnoErr; ?> < /span> Address Line 01 : <input type="text" size="48" name="addressline1" value="<?php echo $addressline1;?>"> <span class="error" style="background-color:#FF0000">* <?php echo $addressline1Err;
    ?></span > Address Line 02: < input type = "text"
    size = "48"
    name = "addressline2"
    value = "<?php echo $addressline2;?>" > < span class = "error"
    style = "background-color:#FF0000" > * <? php echo $addressline2Err; ?> < /span> City : <input type="text" size="48" name="city" value="<?php echo $city;?>"> <span class="error" style="background-color:#FF0000">* <?php echo $cityErr;
    ?></span > Postal Code: < input type = "text"
    size = "48"
    name = "postalcode"
    value = "<?php echo $postalcode;?>" > < span class = "error"
    style = "background-color:#FF0000" > * <? php echo $postalcodeErr; ?> < /span> Country : <input type="text" size="48" name="country" value="<?php echo $country;?>"> <span class="error" style="background-color:#FF0000">* <?php echo $countryErr;
    ?></span > Email: < input type = "text"
    size = "48"
    name = "email"
    value = "<?php echo $email;?>" > < span class = "error"
    style = "background-color:#FF0000" > * <? php echo $emailErr; ?> < /span> Fill the below section if you are submitting abstract only. Otherwise ignore it. <br / > Abstract Details: < textarea name = "abstractdetails"
    rows = "5"
    cols = "40" > <? php echo $abstractdetails; ?> < /textarea> <p>Click the button to display an alert box:</p > < button > Save < /button> <input type="reset" name="submit" value="Cancel" align="middle"> <br><br></div > < /form> </table >

Answer 3

如果你使用的是带有 ajax + jquery + php 的 JavaScript，你可以直接粘贴这段代码

<form method="" action="target.php" id="add_form" autocomplete="off">

   <div class="col-md-12 mx-auto">

        <div class="form-group">
            <label for="car-name">ADD / CREATE ITEM</label>
            <input type="text" id="car-name" name="car_name" class="form-control" >
        </div>
        <div class="form-group">
            <input type="submit" class="btn btn-primary form-control" value="Add item">
        </div>

    </div>

</form>

// 如果您在 .html 或 .php 页面上，可以将其放入 <script></script> 标签中

$(document).ready(function(){
    $("#add_form").submit(function(evt) {
    evt.preventDefault();
    //sending data information
    var postData = $(this).serialize();         //alert(postData);
    //sending url
    var url = $(this).attr('action');           //alert(url);

    // sending data
    $.post(url, postData, function(php_table_data){

        $("#car_result").html(php_table_data);
        window.location.reload();
    });

});

});

** .php 代码**

if(isset($_POST['car_name'])) {

$car_name = $_POST['car_name'];

    if(!empty($car_name)) {

        $query = "INSERT INTO tableName(Columnname) VALUES('$car_name') ";
        $update_car_name = mysqli_query($connection, $query);

            if(!$update_car_name) {

                die("QUERY FAILED");

            }

    } else {
        echo "<script>alert('this field cannot be empty')</script>";
    }


} else {
    header("Location: index.php");
}