What is the usage of the Echo structure in PHP?

In PHP, the Echo structure is used to output the value of data or variables to the browser or command line. Its syntax is:

echo 输出内容;

The output content can be a string, variable, array, etc. Here is an example:

$name = "Alice";
echo "Hello, $name!"; // 输出：Hello, Alice!

The Echo structure can be used in HTML tags to dynamically generate webpage content. For example:

$name = "Bob";
echo "<h1>Welcome, $name!</h1>"; // 输出：<h1>Welcome, Bob!</h1>