Question: I want to write a php page in which there is a html form. I want to send all input (number for example) of my form to a php function (instead of a javascript function; I make this to hide my javascript function code). 

How can I send input value to php function?  

Is it possible to call the php function through `onclick="function(param1, param2)"`?  

I know that javascript is a client-side language while php is server-side.

If it is possible, how can I write the return of the function in an input field?  

I want to remain in my page.  

Is it correct - `action="#"`?  

My code is:

```
<form action="#" method="get">
    Inserisci number1: 
    <input type="text" name="val1" id="val1"></input>

    <?php echo "ciaoooo"; ?>

    <br></br>
    Inserisci number2:
    <input type="text" name="val2" id="val2"></input>

    <br></br>

    <input type="submit" value="send"></input>
</form>

```

Help me in the implementation of the simple php function and in the passage of values from input to function!
Thanks!

Answer: 
Make your `action` empty. You don't need to set the `onclick` attribute, that's only javascript. When you click your submit button, it will reload your page with input from the form. So write your PHP code at the top of the form. 

```
<?php
if( isset($_GET['submit']) )
{
    //be sure to validate and clean your variables
    $val1 = htmlentities($_GET['val1']);
    $val2 = htmlentities($_GET['val2']);

    //then you can use them in a PHP function. 
    $result = myFunction($val1, $val2);
}
?>

<?php if( isset($result) ) echo $result; //print the result above the form ?>

<form action="" method="get">
    Inserisci number1: 
    <input type="text" name="val1" id="val1"></input>

    <?php echo "ciaoooo"; ?>

    <br></br>
    Inserisci number2:
    <input type="text" name="val2" id="val2"></input>

    <br></br>

    <input type="submit" name="submit" value="send"></input>
</form>

```
No, the action should be the name of php file. With on click you may only call JavaScript. And please be aware the hiding your code from the user undermines trust. JS runs on the browser so some trust is needed.