How to run a PHP function from an HTML form?

I'm absolute beginner in web technologies. I know that my question is very simple, but I don't know how to do it. For example I have a function:

function addNumbers($firstNumber, $secondNumber)
{
    echo $firstNumber + $secondNumber;
}

And I have a form:

<form action="" method="post">
<p>1-st number: <input type="text" name="number1" /></p>
<p>2-nd number: <input type="text" name="number2" /></p>
<p><input type="submit"/></p>

How can I input variables on my text fields and call my function by button pressing with arguments that I've wrote into text fields? For example I write 5 - first textfield, 10 - second textfield, then I click button and I get the result 15 on the same page. EDITED I've tried to do it so:

$num1 = $POST['number1'];
$num2 = $POST['number2'];
addNumbers($num1, $num2);

But it doesn't work, the answer is 0 always.

标签： php forms function action

5条回答

我只想做你的唯一

2楼-- · 2019-03-11 10:46

The variables will be in the $_POST variable.

To parse it to the function you need to do this:

addNumbers($_POST['number1'],$_POST['number2']);

Be sure you check the input, users can add whatever they want in it. For example use is_numeric() function

$number1 = is_numeric($_POST['number1']) ? $_POST['number1'] : 0;

Also, don't echo inside a function, better return it:

function addNumbers($firstNumber, $secondNumber)
{
    return $firstNumber + $secondNumber;
}

// check if $_POST is set
if (isset($_POST['number1']) && isset($_POST['number2']))
{
    $number1 = is_numeric($_POST['number1']) ? $_POST['number1'] : 0;
    $number2 = is_numeric($_POST['number2']) ? $_POST['number2'] : 0;

    echo addNumbers($_POST['number1'],$_POST['number2']);
}

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太酷不给撩

3楼-- · 2019-03-11 10:56

You need to gather the values from the $_POST variable and pass them into the function.

if ($_POST) {
  $number_1 = (int) $_POST['number1'];
  $number_2 = (int) $_POST['number2'];
  echo addNumbers($number_1, $number_2);
}

Be advised, however, that you shouldn't trust user input and thus need to validate and sanitize your input.

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等我变得足够好

4楼-- · 2019-03-11 10:57

Try This.

  <?php 
            function addNumbers($firstNumber, $secondNumber)
            {
            if (isset($_POST['number1']) && isset($_POST['number2']))
            {
                $firstNumber = $_POST['number1'];
                $secondNumber = $_POST['number2'];
                $result = $firstNumber + $secondNumber;
                    echo $result;
            }

            }
    ?>

            <form action="urphpfilename.php" method="post">
            <p>1-st number: <input type="text" name="number1" /></p>
            <p>2-nd number: <input type="text" name="number2" /></p>
            <?php addNumbers($firstNumber, $secondNumber);?>
            <p><?php echo $result; ?></p>
            <p><input type="submit"/></p>

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男人必须洒脱

5楼-- · 2019-03-11 11:04

The "function" you have is server-side. Server-side code runs before and only before data is returned to your browser (typically, displayed as a page, but also could be an ajax request).

The form you have is client-side. This form is rendered by your browser and is not "connected" to your server, but can submit data to the server for processing.

Therefore, to run the function, the following flow has to happen:

Server outputs the page with the form. No server-side processing needs to happen.
Browser loads that page and displays the form.
User types data into the form
User presses submit button, an HTTP request is made to your server with the data.
The page handling the request (could be the same as the first request) takes the data from the request, runs your function, and outputs the result into an HTML page.

Sample PHP script that does all of this:

<?php

function addNumbers($firstNumber, $secondNumber) {
    return $firstNumber + $secondNumber;
}

if (isset($_POST['number1']) && isset($_POST['number2'])) {
    $result = addNumbers(intval($_POST['number1']), intval($_POST['number2']));
}
?>
<html>
<body>

    <?php if (isset($result)) { ?>
        <h1> Result: <?php echo $result ?></h1>
    <?php } ?>
    <form action="" method="post">
    <p>1-st number: <input type="text" name="number1" /></p>
    <p>2-nd number: <input type="text" name="number2" /></p>
    <p><input type="submit"/></p>

</body>
</html>

Please note:

Even those this "page" contains both PHP and HTML code, your browser never knows what the PHP code was. All it sees is the HTML output that resulted. Everything inside <?php ... ?> is executed by the server (and in this case, echo creates the only output from this execution), while everything outside the PHP tags — specifically, the HTML code — is output to the HTTP Response directly.
You'll notice that the <h1>Result:... HTML code is inside a PHP if statement. This means that this line will not be output on the first pass, because there is no $result.
Because the form action has no value, the form submits to the same page (URL) that the browser is already on.

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Juvenile、少年°

6楼-- · 2019-03-11 11:05

You are missing the underscores in

$_POST['number1']

That's all.

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How to run a PHP function from an HTML form?

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