What potential issues can arise if the PHP code executes before the form is submitted, as described in the forum thread?

If the PHP code executes before the form is submitted, it may result in undefined variables or errors since the form data has not been processed yet. To solve this issue, you can check if the form has been submitted using the isset() function before executing any code that relies on the form data. 

if(isset($_POST['submit'])) {
    // Process form data here
}

Keywords

PHP code form submission execution order server-side validation security vulnerability

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