First PHP page for Hello world output and checking installation with phpinfo() and uses of comments
echo 'Hello world'; // this part is commented and not displayed
//echo 'This will not be displayed as commented';
#echo 'this is also commented';
Output is here
Multiple Line comments
To comment more than one line or a block of code we can write like this
/* echo ' This is commented ';
echo 'This is also commented ';
echo 'this is also commented, so not displayed';
echo 'this is displayed';
Output is here
this is displayed
In this type of code we must write a stop comment also like */ along with start comment like /*
We can comment to part of the line also.
$v1=3 + /*4 + */ 5;
Here output is 8 ( Not 12 as 4 is not added )
Comments are used in php to not to execute a part or a line of code. Use of comments is a good practice and it helps in code maintenance for future modification and updating. By using comments we can comment or stop executing on a part of a line or in a block of code.
You can read the HTML comments also. Here basic difference between html comment and php comment is in case of php comments; server never sends them to browser, where as all html comments are posted to browser but browser stops displaying them. Any one can see html comments by checking the view – source of the page.
The comments are inserted in any part of the PHP code.
// Single line comment
# Single Line comment
/* ---- */ Multi line comment