Introduction: With the continuous development of the internet, online voting has become a common method to collect user opinions and feedback. To ensure a great user experience across all devices, responsive design is essential. This article will provide a detailed guide on how to build a responsive online voting platform using PHP, accompanied by practical code examples to demonstrate each step.

[h3]1. System Requirements and Design[/h3]

Before developing the online voting platform, it is important to clarify the system’s functional requirements, which mainly include:

• Users can browse all voting options and cast their votes.
• Users can view real-time voting results, including vote counts and percentages for each option.
• Administrators can create, edit, and delete votes and options.
• The system adopts responsive design to support multiple devices and screen sizes.

[h3]2. Database Design[/h3>

To store voting and option information, two main tables are designed:

• vote table: contains voting titles and creation timestamps.
• option table: contains option names, vote counts, and associated vote IDs.

[h3]3. Frontend Interface Design and Development[/h3]

The frontend is built using HTML, CSS, and JavaScript. Media queries are utilized to implement a responsive layout ensuring good display on different devices. AJAX technology (such as Fetch API or jQuery) is used to asynchronously load and update voting data, improving user experience.

<script>
    // JavaScript code
</script>

[h3]4. Server-side Development[/h3]

The server side uses PHP to handle voting requests and data retrieval, supporting POST requests to submit votes and GET requests to fetch voting information. Below is a basic example demonstrating request handling logic:

<?php
// Handle voting requests
if ($_SERVER["REQUEST_METHOD"] == "POST") {
    $vote_id = $_POST["vote_id"];
    $option_id = $_POST["option_id"];

    // Increase vote count for the option
    // $votes = get_votes($option_id);
    // update_votes($option_id, $votes + 1);

    // Return result
    // echo json_encode([
    //     "success" => true,
    //     "message" => "Vote success!"
    // ]);
}

// Handle requests to get voting options and results
if ($_SERVER["REQUEST_METHOD"] == "GET") {
    $vote_id = $_GET["vote_id"];

    // Return voting options and results
    // echo json_encode([
    //     "options" => get_options($vote_id),
    //     "results" => get_results($vote_id)
    // ]);
}
?>

[h3]5. Backend and Database Interaction[/h3]

The backend functions include creating votes, adding options, querying and updating vote counts. It is recommended to use PDO or mysqli extensions for secure database operations.

<?php
function create_vote($title) {
    // Insert record into vote table
}

function add_option($vote_id, $name) {
    // Insert record into option table
}

function get_votes($option_id) {
    // Query option table record
}

function update_votes($option_id, $votes) {
    // Update option table record
}

function get_options($vote_id) {
    // Query option table records
}

function get_results($vote_id) {
    // Query option table records
}
?>

[h3]Conclusion[/h3>

With the design approach and code examples introduced in this article, you can build a fully functional and multi-device compatible PHP online voting platform. Responsive design ensures users enjoy a smooth voting experience whether on mobile phones, tablets, or computers. Hopefully, this tutorial will assist your project development.