What is the problem related to simultaneous clicking from two different browsers in a shop while using PHP?

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The problem related to simultaneous clicking from two different browsers in a shop while using PHP is known as a race condition. It happens when two or more users try to access and modify the same resources or web pages simultaneously. This can lead to unexpected and unwanted results such as duplicate orders, incorrect inventory counts, and incorrect pricing. To prevent race conditions in PHP, developers can use synchronization techniques such as locks and semaphores to ensure that only one user can access and modify a resource at a time.