html form php function action

How can I execute a PHP function in a form action?

stackoverflow.com › questions › 595358 › how-can-i-execute-a-php-function-in-a-form-action

<?php
require_once ( 'username.php' );

if (isset($_POST['textfield'])) {
    echo username();
    return;
}

echo '
<form name="form1" method="post" action="">
  <p>
    <label>
      <input type="text" name="textfield" id="textfield">
    </label>
  </p>
  <p>
    <label>
      <input type="submit" name="button" id="button" value="Submit">
    </label>
  </p>
</form>';
?>

You need to run the function in the page the form is sent to.

Answer from Jeremy L on Stack Overflow

Stack Overflow

stackoverflow.com › questions › 595358 › how-can-i-execute-a-php-function-in-a-form-action

How can I execute a PHP function in a form action? - Stack Overflow

Top answer

1 of 7

<?php
require_once ( 'username.php' );

if (isset($_POST['textfield'])) {
    echo username();
    return;
}

echo '
<form name="form1" method="post" action="">
  <p>
    <label>
      <input type="text" name="textfield" id="textfield">
    </label>
  </p>
  <p>
    <label>
      <input type="submit" name="button" id="button" value="Submit">
    </label>
  </p>
</form>';
?>

You need to run the function in the page the form is sent to.

2 of 7

In PHP functions will not be evaluated inside strings, because there are different rules for variables.

<?php
function name() {
  return 'Mark';
}

echo 'My name is: name()';   // Output: My name is name()
echo 'My name is: '. name(); // Output: My name is Mark

The action parameter to the tag in HTML should not reference the PHP function you want to run. Action should refer to a page on the web server that will process the form input and return new HTML to the user. This can be the same location as the PHP script that outputs the form, or some people prefer to make a separate PHP file to handle actions.

The basic process is the same either way:

Generate HTML form to the user.
User fills in the form, clicks submit.
The form data is sent to the locations defined by action on the server.
The script validates the data and does something with it.
Usually a new HTML page is returned.

A simple example would be:

<?php
// $_POST is a magic PHP variable that will always contain
// any form data that was posted to this page.
// We check here to see if the textfield called 'name' had
// some data entered into it, if so we process it, if not we
// output the form.
if (isset($_POST['name'])) {
  print_name($_POST['name']);
}
else {
  print_form();
}

// In this function we print the name the user provided.
function print_name($name) {
  // $name should be validated and checked here depending on use.
  // In this case we just HTML escape it so nothing nasty should
  // be able to get through:
  echo 'Your name is: '. htmlentities($name);
}

// This function is called when no name was sent to us over HTTP.
function print_form() {
  echo '
    <form name="form1" method="post" action="">
    <p><label><input type="text" name="name" id="textfield"></label></p>
    <p><label><input type="submit" name="button" id="button" value="Submit"></label></p>
    </form>
  ';
}
?>

For future information I recommend reading the PHP tutorials: http://php.net/tut.php

There is even a section about Dealing with forms.

PHP

php.net › manual › en › tutorial.forms.php

PHP: Dealing with Forms - Manual

Here is an example HTML form: ... <form action="action.php" method="post"> <label for="name">Your name:</label> <input name="name" id="name" type="text"> <label for="age">Your age:</label> <input name="age" id="age" type="number"> <button type="submit">Submit</button> </form>

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