What is the significance of the "register globals" setting in PHP and how does it affect form data processing?

The "register globals" setting in PHP allows form data to be automatically turned into global variables, which can lead to security vulnerabilities such as injection attacks. To solve this issue, it is recommended to disable the "register globals" setting in the php.ini file or within the PHP script itself using the ini_set() function.

// Disable register globals in PHP script
ini_set('register_globals', 0);