Functional testing, also known as behavioral testing, tests the characteristics and actionable behavior of a product based on product characteristics, operational descriptions, and user scenarios to determine that they meet design requirements. Functional testing of localized software to verify that the application or website works correctly for the target user. Use appropriate platforms, browsers, and test scripts to ensure that the target user experience will be good enough, just as the application is specifically developed for that market. Functional testing is the testing of software according to functional requirements to ensure that the program runs in the expected manner. It ensures compliance with requirements and specifications by testing all features and functions of a system. Functional testing, also known as black box testing or data-driven testing, only needs to consider the various functions that need to be tested, without considering the internal structure and code of the entire software. Generally, starting from the interface and architecture of the software product, test cases are written according to the requirements, and input data is evaluated between the expected and actual results, in order to propose to better meet the user's requirements for the product. Testing in the application of electronic technology: Printed circuit board, also known as printed circuit board, often abbreviated as PCB (Printed Circuit Board), is an important electronic component, a support body for electronic components, and a provider of electronic component wiring connections. Due to its use of electronic printing technology, it is called a "printed" circuit board. Before the emergence of printed circuit boards, the interconnection between electronic components relied on direct connection of wires to form a complete circuit. Circuit breadboards exist only as effective experimental tools, while printed circuit boards have become an absolute dominant position in the electronics industry