Novice, questions about PHP?

Novice, would like to ask how the following code is working:

  
       This is true.
  
       This is false.
  
   

The actual situation is: $expression if it exists or is correct, displays this is true. The error displays this is false.
But how does this work?
This is true. not in the middle, should it be displayed directly? How is this judgment implemented? Just learn php small white, ask for answers!

Reply content:

Novice, would like to ask how the following code is working:

  
       This is true.
  
       This is false.
  
   

The actual situation is: $expression if it exists or is correct, displays this is true. The error displays this is false.
But how does this work?
This is true. not in the middle, should it be displayed directly? How is this judgment implemented? Just learn php small white, ask for answers!

, but it doesn't mean it's a separate piece.

你的代码对电脑来说 就是phphtmlphphtmlphp

They are a whole, this is for the computer to see, you read the code when you use the brain to filter it out.

Have you seen much of your textbook?
if($expression){//your code}
If this is true, execute {}

That's what you're talking about:

You should understand PHP what, PHP is hypertext preprocessor, hypertext preprocessor, it is a standard scripting language, whether Apache or Nginx, these codes are pre-processed by the PHP interpreter, PHP first read all the Tag blocks of code, and then execute these blocks of code, and output the resulting data, and eventually all the stdout are encapsulated into HTTP response sent to the browser, becoming the last HTML code

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