Скачать или смотреть Comments in Javascript JavaScript Tutorial w3Schools Ch#06 English

JavaScript comments can be used to explain JavaScript code, and to make it more readable.

JavaScript comments can also be used to prevent execution, when testing alternative code.

Single line comments start with //.

Any text between // and the end of the line will be ignored by JavaScript (will not be executed).

Multi-line Comments
Multi-line comments start with /* and end with */.

Any text between /* and */ will be ignored by JavaScript.
It is most common to use single line comments.
Block comments are often used for formal documentation.

Using comments to prevent execution of code is suitable for code testing.

Adding // in front of a code line changes the code lines from an executable line to a comment.

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