Write beautiful code-separate background programs from front-end programs

When writing a PHP program, some code is used to process some transactions, such as database operations and mathematical operations. Other code is only displayed as the result of transaction processing, for example, some PHP code that uses echo statements to display results in HTML format on a Web browser and the HTML code that directly embeds the PHP program. First, we should clearly distinguish the two types of code, the former is called the background program, and the latter is called the front-end program.


Because PHP is an embedded programming language, that is to say, all PHP code can be embedded into HTML code, which brings a lot of convenience for programming. However, if PHP code and HTML code are mixed in a long program, this will make the program messy, not conducive to program maintenance and reading. Therefore, we need to try to port the PHP code in these programs mixed with HTML code, and encapsulate the code into a function in a special file, then, use the include statement in the HTML code to include these files, and call these functions at the appropriate location.


On the one hand, this method makes HTML code and PHP code easy to read, and on the other hand, because HTML code needs to be constantly updated, and this separation method can ensure that the background program will not be destroyed.
Different from front-end programs, background programs are more stable, structured, and rarely changed. Therefore, they should be carefully designed and managed. In fact, it is worthwhile to invest a lot of time in the design of a program. "planting trees now and enjoying the cold in the future" will make it easy to use the background program compiled in the future design work.