如何使表单仅在按钮点击时提交而不是刷新？

Question

I have a form where i should make the form submit(request to a service) only if the form field is changed, If the field is not changed when the user refresh the page it should not submit the form again.

OBJECTIVE is to reduce the number of form submission as possible, So if the user has the same entered data and he refresh, we shouldn't waste the previous returned datas and try to give new request and show the same datas.

Instead it should be submitted only if the TEXT(searchdirectory) is changed. So there won't be repeating request for same datas.

<form method="post" action="<?php echo $_SERVER['PHP_SELF'];?>">            
        <label>TEXT :</label>
        <input type="text" id="search_dir" name="searchdirectory"
            value="<?php
                    if (isset($_POST['searchdirectory']))
                    {
                        echo($_POST['searchdirectory']); 
                    }
                   ?>"
        />            
        <input type="submit" value="Search" name="submit" id="searchB"/>
        <?php            
            if (isset($_POST['submit'])) 
            {
             //functions  to show results queried from searchdirectory
            }
        ?>
    </form>

I guess this would be to deal with refresh behaviour of browsers, Is there a way to stop the form submission if user refresh the page. It should show the same datas.

Answer 1

Use redirect when form data was sent at first.

<?php            
    if (isset($_POST['submit'])) 
    {
        //do function
        header("Location: http://". $_SERVER['HTTP_HOST'] . $_SERVER['PHP_SELF']);
    }
?>

Where "http://". $_SERVER['HTTP_HOST'] . $_SERVER['PHP_SELF'] - is a link to which the user will be redirected after form submit.