Definition and Usage The sqrt() method returns the square root of a number. Syntax Math.sqrt(x) Parameter Description ...

## Definition and Usage

The sqrt() method returns the square root of a number.

## Syntax

Parameter | Description |

x | Required. A number |

## Tips and Notes

**Note:** The sqrt() method will return NaN if the parameter x is a negative number.

## Example

In this example we will get the square root of different numbers:

<script type="text/javascript"> document.write(Math.sqrt(0) + "<br />");
document.write(Math.sqrt(1) + "<br />");
document.write(Math.sqrt(9) + "<br />");
document.write(Math.sqrt(0.64) + "<br />");
document.write(Math.sqrt(-9)); </script> |

The output of the code above will be: