What a comment looks like in the document code. Comments in HTML, CSS, JS and PHP code

I'll start this article with what comments are for. Let's assume that you are developing a module with a complex structure. Or you make a layout with many nested elements. In such cases, it is best to mark some sections of the code somehow - that is what comments are for.

Now I will show in detail four types of comments, or rather, all their types for four different codes.

Comments in HTML markup

To add a comment to HTML markup, use:

Everything that appears in these tags is not visible on the screen, but is available for viewing in the source code.

Comments in CSS styles

To add a comment to CSS styles, use:

Everything that appears in these tags is not taken into account when creating styles, but is available for viewing in the styles file itself.

Comments in JavaScript code

To add comments in JavaScript there are two types.

First type:

// Text, code or other

Second type:

/* Text, code or other */

Anything in these tags is not taken into account when the script is executed, but is available for viewing in the JavaScript file itself.

Comments in PHP code

This programming language, unlike previous ones, has 3 types of comments.

First type:

// Text, code or other

Second type:

/* Text, code or other */

And the third type:

# Text, code or other

Everything that appears in these tags is not taken into account when the script is executed and is only visible in the PHP file itself.

Note!

/* /* My code */ */

will give you an error.

Michael 2016-05-06 1 HTML and CSS 0

How to write in css comments in code?

I believe that leaving css comments in the code is a very good form of a web developer. Firstly, it’s clearer to him. Secondly, it becomes much clearer to those who did not write this code, but are trying to understand it. I believe that the presence of comments is one of the signs of the professionalism of a web developer. But how to write them in the same css?

How to write comments in css code?

Everything here is as simple as possible and similar to how they are done in programming languages. Multi-line (and even single-line) comments can be done like this:
/* text here */

Everything should start with a slash and an asterisk, and to close a comment use the reverse construction (first an asterisk, then a slash). In code editors, comments are highlighted differently, in Notepad++, for example, green. In this screenshot you can see how I commented out the styling for the input elements.

Why are they needed?

CSS requires even more comments than html. This is due to the fact that the css code is usually always larger and is more often edited when changing ready-made template. Since there can be 5-10 times more lines here than in the markup, it won’t be so easy to figure out where which styles are without comments.

For example, in the standard layout of an average layout there are 500-1000 lines css code responsible for the styling of the elements. At the same time, I have repeatedly seen files 5-10 times larger. In this regard, it is good practice to leave comments during layout. Here is an example of their use:

That’s it, the readability and perception of the rules written later will be much better even for a beginner, but an experienced developer will understand it even more. In general, use them in your layout.

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Comment tagsin HTML code are used to temporarily disable the code (as a rule, simply deleting the code is inconvenient for the reason that you may have to restore it) and as a hint for yourself or for people who will understand your code. The text inside the comment is not displayed by the browser on the page.

Comments can be used anywhere on the page except in the tag Page content.

Conditional comments.

Conditional comments are used to write special code, designed for a specific browser ( Internet Explorer). Other browsers ignore this code as a regular comment.

For example:

Код HTML

The code is executed only when the specified condition is met. In this case, if Internet browser Explorer 7, then you need to execute the code that we will place inside the tag.

Other examples: Инструкции для всех Internet Explorer Инструкции для всех IE меньше или равно 6 Инструкции для всех IE старше или равно 7

Meaning of operators.

In this lesson I will talk about how to make comments in HTML, CSS, PHP. Comments are text that is not visible on the web page. They are used for various kinds of explanations, reminders, and descriptions for webmasters, which allows you to structure the document. Comments are indispensable when debugging code; they allow you to quickly navigate the markup of a web page and find the desired block. Comments are often used to debug HTML code. For example, you can temporarily comment out a specific block of code so that it is not executed, and if necessary, you can easily restore it.

Comments in HTML

In HTML, comments are formed using the following characters:. Thus, any text between these characters is a comment. Let's look at an example:

Example of comments in HTML

Comments in CSS

Comments in CSS are created using the characters: /* and */. To create a comment, you simply need to place the web page code between these characters:

/* Start of a block with styles for Body*/ body ( background: #efeded; font-family: Verdana, Helvetica, sans-serif; font-size: 12px; margin: 0px; padding: 0px; ) /* End of a block with styles for Body*/

Comments in PHP

Comments in PHP can be single-line or multi-line:

1) Single-line comments in PHP are created using the characters: //. Simply put this character in front of the line and it will be commented out. This option is used in the case when the comment consists of only one line.

2) To implement multi-line comments, the following symbols are used: /* and */. This option is useful if the comment spans several lines.

So we learned to do

Before you learn how to make comments in HTML, you need to understand what they are for. If you are interested in such information, then you probably already know, so we will not dwell on this issue. Some people don't pay enough attention to the placement of comments in their code. In one-page sites, such an error may go unnoticed. But when it comes to huge portals, small comments will save time and make your life easier. Plus, notes allow other developers to understand your code when additional explanation is needed.

Target

Creating an HTML page is sometimes impossible without confusing codes and ever-repeating tags. New classes, selectors, id indicators, etc. All this can literally drive you crazy. HTML comments are designed to ease the plight of web developers. After all, when the site code stretches far down, it can be difficult to remember what is where. It is comments that help you make small notes directly in the html code that will not be visible to your users. Beginners rarely use this tag. But experienced specialists highlight the huge, useful property of comments. This tag is especially effective when several developers are working on the code at once. Instead of asking questions every time and interrupting your partner from work, you just need to look through the comments.

Creation

In order for a new line with a comment to appear in your code, you need to add the following entry:. This is exactly what this tag looks like in html. Whatever is inside it will not be displayed on the users' screen. Html comments should not stretch over several lines and contain any code (this is considered bad form). They should only provide some description of the developer's intent regarding the insertion of that particular tag, attribute, or value. Although among high level There is an opinion among experts that the code should be written in such a way that no additional explanation is required. But, unfortunately, not everyone has such a gift for writing HTML pages.

Peculiarities

Taghas some of its own characteristics. For example, you can add any other tags inside it, but you cannot create nested comments. This will lead to a not entirely expected result. Comments in html are widely used for testing web pages. For example, when you need to look at a website without specific tag, but you cannot delete it, as it will be difficult to restore all source. In this case, you just need to place the required part of the page in the comments. And then the tag will be ignored by the browser. But it is worth noting that all comments can be traced if you open the source code of the page. And every user can do this. Therefore, you should not place any important information inside this tag.