Retaining form data value after posting

Retain form values safely

A sticky form can redisplay valid user input after a validation error. Escape the value before placing it back inside an HTML attribute.

$name = trim($_POST['name'] ?? '');
$safeName = htmlspecialchars($name, ENT_QUOTES, 'UTF-8');

echo '<input type="text" name="name" value="' . $safeName . '">';

Retaining text box value
Retaining checkbox value
Retaining dropdown list
Retaining period button
Using JavaScript to retain data

Many times we have to show the visitors posted data in a form and show them the form again. This happens due to several reasons and one of the main reason is failure of entered data or failure of data validation.

DEMO : Form all components validation and post back→

In an example say the visitor has entered all the details in a signup form but the user id entered by the member is already used by some one else. Such a situation can be checked only after the visitor enters his or her choice of id. In such a case we have to show one error message and ask the user to try one more user id. ( you can see how the signup form works with to total login script etc here ) Here if the user has already entered all other details like email, address, gender etc then it is not a good idea to ask the visitor to enter them again. We can retain the entered date in respective fields and ask for necessary change in selection of user id.

So the main question is how to retain the value of the entered data in different components of the form. If some one has selected female as gender then the form should retain that value and by default should show female as selected. Same way all input text box, drop down list box and check box should retain the value already entered by the user.

For most sticky forms, submit with POST and redisplay the validated values on the same page. Avoid putting personal or sensitive form values into the query string because URLs can be logged, bookmarked, or shared. If you use a redirect-after-POST workflow, keep only non-sensitive state or a short server-side reference in the redirect.

For the HTML structure behind these examples, see the HTML form tutorial.

We will discuss post back of data of each component of a form. We will start with a simple text box and move to other form components like period button, drop down list, text area and check box. We will focus one component in one tutorial and at the end we will create DEMO form using all the components using all our learning.

Retaining value of a text box component of a form

← PHP Form Listbox in a Form using PHP → Checkbox in PHP → Radio buttons →

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