Setting A $_GET Value From A Previously Defined Variable

I have a search form in the header of every page on a site that submits info to another page when undertaking a search query via the form's action attribute, namely a page called search.php and it takes the value of the search <input> field and stores it as a variable called searchQuery. Using PHP this searches a MySQL database. All of this works as expected.

I would like the value of the search input field to be placed in the URL of the page the search is processed on, again namely search.php.

I understand from other questions on SO that you can't add variables to a form's action attribute. If I add the key of the query string in the action attribute, the form still works OK:

action="search.php?keyword="

From this I thought I would be able to then set the $_GET value on the search.php page by using:

if(isset($_POST['search-submit'])) {

    // make this variable available before HTML output
    $searchQuery = htmlspecialchars($_POST['search']);

    $_GET['keyword'] = $searchQuery;
}

This however does not work, although it doesn't throw any errors in my PHP error logs.

Because I'm running the script on specific page allocated by the action attribute, I don't think I need to use a $_SESSION variable?

HTML Form

Here is the form that is on every page in the header

<form action="search.php?keyword=" method="POST">
    <label for="search">Enter Search</label>
    <input type="search" name="search" id="search">
    <button type="submit" name="search-submit" id="search-submit">Search</button>
</form>

CodePudding user response：

In your form set the method to GET, remove the query string from the action attribute so it is just search.php, change the name on the search input field to keyword and remove the name on the submit button.

<form action="search.php" method="GET">
    <label for="search">Enter Search</label>
    <input type="search" name="keyword" id="search">
    <button type="submit" id="search-submit">Search</button>
</form>

Then in your search.php page, change your initial code to the following:

if(isset($_GET['keyword'])) {
    // make this variable available before HTML output
    $searchQuery = htmlspecialchars($_GET['keyword']);
} else {
    header("Location: index.php"); // use whatever page is your home page or preferred page to redirect to
}

And then in your search query make sure the $_GET value is set:

if(isset($_GET['keyword'])) {

    // run your search query using the $searchQuery variable

}