PHP为什么会这样？ [重复]

Question

This question already has an answer here:

• How can I echo HTML in PHP? 13 answers

Specifically speaking, why does the below code work (outputs "test").

<?
    $variable = 'test';
?>

<?=$variable?>

Is this hacky, or functionality?

</div>

Answer 1

<?=?> is a Short Tag for echo(); According to PHP

Outputs all parameters.

echo is not actually a function (it is a language construct), so you are not required to use parentheses with it. echo (unlike some other language constructs) does not behave like a function, so it cannot always be used in the context of a function. Additionally, if you want to pass more than one parameter to echo, the parameters must not be enclosed within parentheses.

echo also has a shortcut syntax, where you can immediately follow the opening tag with an equals sign. Prior to PHP 5.4.0, this short syntax only works with the short_open_tag configuration setting enabled.

Gives you the also the next example:

I have <?=$foo?> foo.