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.

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JavaScript statements are composed of: Values, Operators, Expressions, Keywords, and Comments. This statement tells the browser to write "Hello Dolly." inside an HTML element with id="demo":

JavaScript Comments. Not all JavaScript statements are "executed". Code after double slashes // or between /* and */ is treated as a comment. Comments are ignored, and will not be executed:

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CSS Comments. Comments are used to explain the code, and may help when you edit the source code at a later date. Comments are ignored by browsers. A CSS comment is placed inside the <style> element, and starts with /* and ends with */:

HTML comments are not displayed in the browser, but they can help document your HTML source code.

The comment tag is used to insert comments in the source code. Comments are not displayed in the browsers. You can use comments to explain your code, which can help you when you edit the source code at a later date.

JavaScript Coding Conventions. Coding conventions are style guidelines for programming. They typically cover: Naming and declaration rules for variables and functions. Rules for the use of white space, indentation, and comments. Programming practices and principles. Coding conventions secure quality: Improve code readability; Make code ...