为什么只有PHP允许在HTML代码中，但其他语言使用CGI？ [关闭]

Question

For example, why developers of Python don't make the interpreter for using Python like PHP in HTML code?

I hope my question is not very stupid, if so, sorry about that.

Answer 1

PHP was initially designed primarily as a programming language for creating web applications (the name stands for Personal Home Page). To make this easier, they tightly integrated the language into the web pages. In fact, in early versions of PHP, the code was embedded in HTML comments (similar to the way early Javascript had to be embedded). The PHP History page shows examples of this (this was called PHP/FI -- PHP Forms Interpreter):

<!--include /text/header.html-->

<!--getenv HTTP_USER_AGENT-->
<!--ifsubstr $exec_result Mozilla-->
  Hey, you are using Netscape!<p>
<!--endif-->

Later on, the name PHP became the recursive acrynym PHP Hypertext Preprocessor. This indicates that it's intended to be embedded in HTML, much the way C preprocessor code is embedded in C and C++ programs.

The embedded nature makes it easy to write web pages with lots of static HTML interspersed with dynamic code. In any other language, you'd need hundreds or thousands of print statements, while PHP allows you to just escape out of scripting mode into raw output for all the static parts.

There's no reason other languages couldn't be embedded into HTML in similar ways. But the designers simply didn't have that as a priority, they intended them as more general purpose languages, so they didn't put this feature into them. PHP can be used as a standalone programming language (my company uses it extensively in cron jobs), it's just not its original design emphasis.