# GeoGebra

## Manual:Scripting

### GeoGebra Objects

Script is a sequence of commands, that are executed one after each other. GeoGebra supports two scripting languages - GGBScript and Javascript. The execution can be triggered by :

• clicking a particular object
• updating a particular object (when value or properties of the object are changed)
• Javascript listeners (see Reference:JavaScript)

You can set this script via Scripting panel of Properties Dialog.

## GGBScript

You can create scripts consisting of GeoGebra commands, like you can use them in the Input Bar. After triggering the script, every command is executed one after each other.

Example:
• a is an integer-valued slider ranging from 1 to 3
• `list1 = {"red", "green", "blue"}`
• in properties of a, set "On Update" script to `SetColor[a, Element[list1, a]]`
• by moving the slider you change its color

Explanation: Every time the slider is moved, there is happening an update. So, for every move the script is called and the value of "a" is used to get one color from the list and change the color of the slider "a".

Hint: There are commands that can be only used for scripting. You can find them in the page Scripting_Commands.

## JavaScript

JavaScript is a programming language used by many Internet technologies. Unlike GeoGebra Script, in Javascript the commands don't have to be executed as a simple sequence, but a control flow (`if`, `while`, `for`) can be used. For generic JavaScript you can find a nice tutorial on developer.mozilla.org. In GeoGebra, you can use special JavaScript methods which allow you to change the construction. These methods belong to ggbApplet object, which means that you call them as `ggbApplet.method_name(parameter,..,parameter)`. For complete list of these methods see Reference:JavaScript.

Example:
```for(var i =0;i<10;i++)
ggbApplet.evalCommand("A_"+i+"=(random()*10,random()*10)");
```
This script creates 10 points A0 to A9 at random coordinates.

GeoGebra contains its own JavaScript engine. When exported as Dynamic Worksheet one can choose whether to use this engine or the one contained in browser applets. If you edit JavaScript in a HTML page, the ggbApplet variable will not be initialized, you have to initialize it e.g. using `ggbApplet=document.applets[0];` first.

### Global JavaScript

In the Global JavaScript part of Scripting tab in Properties Dialog you may define functions (not variables) which will be available from the other scripts. You can also define function ggbOnInit(), which is called automatically once the construction is loaded. The ggbOnInit function can be used for registering some listeners, as shown below.
Example:
```function onAdd(name){
}

function ggbOnInit(){