A comment is a line of code that contains text, usually an explanation or a note. All comments are ignored during script execution.
### Block
Right click on any block and add a comment
### Touch Develop syntax
To insert a comment in a Touch Develop script:
1. Click a line in your script.
2. Click `+`.
3. Click `// comment` and then type some text (your comment).
### ~hint
To find out how to insert comments using the Blocks editor, see [the Blocks editor](/microbit/blocks/editor).
### ~
### Sample function with comments
This function has comments that describe the purpose of the function:
```
/**
* // square function :
* // returns the square of the input parameter x
*@param x TODO
*/
export function square(x: number) : number {
let result: number
return x * x
return result
}
```
### Formatting
Use [markdown syntax](/microbit/js/markdown) to format your comments (for example, **bold** and *italic* formatting).
### Commenting out code
During the debugging process, you may want to comment out a section of your code so that it doesn't run.
To comment out a block of code:
1. Click the first line of code that you want to comment out.
2. Press and hold the Shift key, and then press the Down arrow key to select a block of code.
3. In the block editing window, scroll down to **surround with** and click `comment out`. This adds an [if](/microbit/reference/logic/if) statement around your code, like this:
```
if (false) {
// the commented code here...
}
```
When you want to uncomment your code, click the `if false then` statement in your code, and then click `uncomment`.
### Library and function comments
* Use [comments](/microbit/js/comment) at the beginning of a library to describe the library
* Use [comments](/microbit/js/comment) at the beginning of a [function](/microbit/js/function) to describe a function. The comment will appear in the help area of the Touch Develop editor when you insert the function
