What are the best practices for handling form submissions in PHP to avoid issues like blank pages or errors in the output?

When handling form submissions in PHP, it's essential to check if the form has been submitted before processing the input data to avoid issues like blank pages or errors in the output. One way to achieve this is by using the `isset()` function to check if the form data has been submitted. Additionally, validating the input data and sanitizing it before using it in the application can help prevent security vulnerabilities. 

<?php
if(isset($_POST['submit'])){
    // Process form data here
    $input_data = $_POST['input_data'];
    
    // Validate and sanitize input data
    $sanitized_data = filter_var($input_data, FILTER_SANITIZE_STRING);
    
    // Output the sanitized data
    echo "Sanitized input data: " . $sanitized_data;
}
?>

Keywords

form submissions PHP error handling output validation

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