Question

I need to have two inputs with a different types:

<input  type="button"  **onclick = "?????"**   name="back"  value="&#8592 Back"  >
<input  type="submit" name="submit" value="Forward &#8594"  >

How can I do for type=button run this PHP code:

<?php

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

        $_SESSION['onpage'] = $_SESSION['onpage'] - 1;

        $query_questionset = "
        select Q.Constructor AS Constructor,
        QS.QuestionIDFKPK AS QuestionIDFKPK,
        Q.QuestionValue AS QuestionValue,
        QS.SortOrder AS SortOrder,
        QS.onpage AS onpage
        from tbluserset AS US
        inner join tblquestionset AS QS ON US.QuestionSetIDFKPK = QS.QuestionSetIDPK
        inner join tblquestion AS Q ON QS.QuestionIDFKPK = Q.QuestionIDPK
        where (US.UserIDFKPK = " . $UserId . ")
        and (US.UserSetIDPK= '" . $_SESSION['UserSetIDPK'] . "')
        and (QS.onpage = '" . $_SESSION['onpage'] . "')
        order by QS.SortOrder";

    }

    $QuestionSet_Constructors = mysql_query($query_questionset);
?>

My form and input submit works perfectly:

<form id= "formID"  class="formular"   method="post" action= "<?= $url = "QUESTIONAREnewdatabase.php"; ?>" accept-charset="utf-8">

What I need on input type=button for run that PHP code and the action form like if Back had type=submit?

Answer 1

Here’s one way that uses Javascript, this will dynamically create and append a hidden input called back to the form, then submit the form – when the back button is clicked.

<script>
    function postBack()
    {
        var myForm = document.getElementById("formID");
        var backInput = document.createElement("input");
        backInput.type = "hidden";
        backInput.name = "back";
        backInput.value = "1";

        myForm.appendChild(backInput);
        myForm.submit();
    }
</script>


<input type="button" onclick="postBack()" name="back" value="&#8592 Back">

On the server side, you can now test for:

if(isset($_POST['back']))
{
    // back was pressed...
}