GeoGebra JavaScript CheatSheet

JAVASCRIPT CHEATSHEET IN GEOGEBRA
JAVASCRIPT CHEATSHEET IN GEOGEBRA PROF. JOSÉ PÉREZ SANABRIA
Single line comments- //
Multi-line comments- /* comment here */
var- The most common variable. Can be reassigned but only
accessed within a function. Variables defined with var move to the
top when code is executed.
const- Cannot be reassigned and not accessible before they appear
within the code.
Numbers- var num = 17;
Variables- var x;
Text (strings)- var a = "algebra";
Operations- var b = 1 + 4+ 9;
True or false statements- var c = true;
Notation Scientific-
var num1=1e10, num2=4e-9;
Constant numbers- const PI = 3.1416;
Basic Operators
+ Addition, - Subtraction, * Multiplication, / Division
(...) Grouping operator, % Modulus (remainder)
Increment/Decrement Numbers
i++ Postfix Increment numbers
i-- Postfix Decrement numbers
++i Prefix Increment numbers
--i Prefix Decrement numbers
var var1 = 5, var2 = 5;
alert(var1++); //5
alert(++var2); //6.0
alert(var1--); //6.0
alert(--var2); //5.0
Assigment and Operators
a += b //a = a + b Add then assign
a -= b //a = a – b Subtract then assign
a *= b //a = a * b Multiply then assign
a /= b //a = a / b Divide then assign
Comparison Operators
== Equal to, != Not equal, > Greater than, < Less than,
>= Greater than or equal to, <= Less than or equal to
Ternary Operator ?- (expression)? ifTrue: ifFalse
function getTF(isMember) {
return (isMember ? 'True' : 'False');
}
alert(getTF(true)+"n"+getTF(false)+"n"+getTF(1));
Logical Operators
&& Logical and-
alert((1 > 0) && (4 > 0));
|| Logical or-
alert((1 > 3) || (4 > 3));
! Logical not-
alert(!(1 == 1));
Bitwise Operators
& AND statement, | OR statement, ~ NOT, ^ XOR,
<< Left shift, >> Right shift, >>> Zero fill right shift
alert("5&1="+(5&1) +
"5|1="+(5|1) +
"~5="+(~5) +
"5<<1="+(5<<1) +
"5^1="+(5^1) +
"5>>1="+(5>>1) +
"5>>>1="+5>>>1);

Functions
function namefunction(parameter1, parameter2, parameter3)
{ // what the function does }
Outputting Data
alert()- Output data in an alert box in the browser window.
alert("Welcome to Geogebra");
prompt()- Creates an dialogue for user input.
var value=Number(prompt("Enter value: ",1));
Global Functions
eval()- Evaluates JavaScript code represented as a string.
alert(eval("x = 2+3"));
var x = 10;
var y = 20;
var a = eval("x * y") ;
var b = eval("2 + 2");
var c = eval("x + 17");
var res = a + b + c;
alert(a+"+"+b+"+"+c+"="+res)
isFinite()- Determines whether a passed value is a finite number.
isNaN()- Determines whether a value is NaN or not.
Number()- Returns a number converted from its argument.
parseFloat()- Parses an argument and returns a floating-point
number.
parseInt()- Parses its argument and returns an integer.
JAVASCRIPT LOOPS
for- The most common way to create a loop in JavaScript.
for (before loop; condition for loop; execute after loop) {
// what to do during the loop }
var str="";
for (var i = 0; i < 10; i++) {
str=str+i + ": " + i*3 + "n";
}
alert(str);
var sum = 0;
for (var i = 0; i < a.length; i++) {
sum + = a[i];
} // parsing an array
while- Sets up conditions under which a loop executes.
var i = 1; // initialize
var str=""; // initialize
while (i < 100) { // enters the cycle if statement is true
i *= 2; // increment to avoid infinite loop
str=str+i + ", "; // output
}
alert(str);
do while- Similar to the while loop, however, it executes at least
once and performs a check at the end to see if the condition is met
to execute again.
do { // enters cycle at least once
i *= 2; // increment to avoid infinite loop
str=str+(i + ", "); // output
} while (i < 100) // repeats cycle if statement is true at the end
alert(str);

break- Use to stop and exit the cycle at certain conditions.
for (var i = 0; i < 10; i++) {
if (i == 5) { break; } // stops and exits the cycle
str=str+(i + ", "); // last output number is 4
}
alert(str);
continue- Skip parts of the cycle if certain conditions are met.
for (var i = 0; i < 10; i++) {
if (i == 5) { continue; } // skips the rest of the cycle
str=str+(i + ", "); // skips 5
}
alert(str);
IF - ELSE STATEMENTS
if (condition) {
// what to do if condition is met
} else {
// what to do if condition is not met
}
if(n%2){
alert("Number is odd.");
}else{
alert("Number is even.");
}
IF - ELSE NESTED STATEMENTS
var number=Number(prompt("Enter number",0));
if (number > 0) {
alert("Positive");
}else if (number < 0) {
alert("Negative");
}else{
alert("Zero");
}
SWITCH STATEMENTS
var n=333;
switch (n%4) {
case 0:
result = "1"; break;
case 1:
result = "i"; break;
case 2:
result = "-1"; break;
case 3:
result = "-i"; break;
default:
result="Null";
}
alert("i^"+n+" = "+result);
Objects Definition and Properties
Initialize Objects- var obj3D = {name:"Sphere", radius:2};
alert("Object="+obj3D.name+"nradius="+obj3D.radius);

Initialize Objects-
var obj2D = { name:"Triangle", area:20, perimeter:24,
type:"rectangle"};
alert("Object=" + obj2D.name+" "+ obj2D.type + "nArea=" +
obj2D.area);
Initialize Objects-
var polygon = new Object();
polygon.type = "quadrilateral";
polygon.property = "trapezoidal";
polygon.area = 50;
polygon.perimeter = 60;
alert(polygon.type+"n"+
polygon.property +"n"+
polygon.area+"n"+
polygon.perimeter);
Initialize Functions in Objects-
var obj = {name: "Straight",
type: "Angle",
getName: function() { alert (this.name);}
};
obj.getName();
Initialize String Array- "
var course = ["Geometry","Trigonometry","Calculus"];
var course= new Array("Geometry", "Trigonometry", "Calculus");
var list1 = [2,3,5,8];
var list1 = new Array(2,3,5,8);
Declare Array Dynamic
var arr=new Array();
Array Methods
arr.length- Returns the number of elements in an array.
arr.concat()- Join several arrays into one.
arr.indexOf()- Returns the primitive value of the specified object.
arr.join()- Combine elements of an array into a single string and
return the string.
arr.lastIndexOf()- Gives the last position at which a given element
appears in an array.
arr.pop()- Removes the last element of an array.
arr.push()- Add a new element at the end.
arr.reverse()- Sort elements in descending order.
arr.shift()- Remove the first element of an array.
arr.slice()- Pulls a copy of a portion of an array into a new array.
arr.sort()- Sorts elements alphabetically.
arr.splice()- Adds elements in a specified way and position.
arr.toString()- Converts elements to strings.
arr.unshift()- Adds a new element to the beginning.
arr.valueOf()- Returns the first position at which a given element
appears in an array.
Initialization of a 2d Array Static
var c[2][3] = {{1, 3, 0}, {-1, 5, 9}};
Set Value Element in 2D Array- c[1][2]=4;
Get Value Element in 2D Array- num=c[2][1];
STRINGS
var CEO="Markus Hohenwarter";
var str= "javascript";
alert(str.length);
length- the length of the string
Escape Characters
' - Single quote, " - Double quote, - Backslash
r - Carriage return, 0 - NUL character
n - A new line characte

String Concatenation
var nside = 3;
alert('Triangles have ' + nside + ' sides.');
String Methods
charAt()- Returns a character at a specified position inside a string.
charCodeAt()- Gives you the unicode of character at that position.
concat()- Concatenates (joins) two or more strings into one.
fromCharCode()- Returns a string created from the specified.
sequence of UTF-16 code units.
indexOf()- Provides the position of the first occurrence of a
specified text within a string.
lastIndexOf()- Same as indexOf() but with the last occurrence,
searching backwards.
match()- Retrieves the matches of a string against a search pattern.
replace()- Find and replace specified text in a string.
search()- Executes a search for a matching text and returns its
position.
slice()- Extracts a section of a string and returns it as a new string.
split()- Splits a string object into an array of strings at a specified
position.
substr()- Similar to slice() but extracts a substring depended on a
specified number of characters.
substring()- Also similar to slice() but cannot accept negative
indices.
toLowerCase()- Convert strings to lower case.
toUpperCase()- Convert strings to upper case.
valueOf()- Returns the primitive value of a string object.
NUMBERS AND MATH
Number Properties
Math.MAX_VALUE- The maximum numeric value representable in
JavaScript.
Math.MIN_VALUE- Smallest positive numeric value representable
in JavaScript.
Math.NaN- The "Not-a-Number" value.
Math.NEGATIVE_INFINITY- The negative Infinity value.
Math.POSITIVE_INFINITY- Positive Infinity value Number Methods.
alert("MAX_VALUE="+Math.MAX_VALUE+
"nMIN_VALUE="+Math.MIN_VALUE+
"nNaN="+Math.NaN+
"nNEGATIVE_INFINITY="+Math.NEGATIVE_INFINITY+
"nPOSITIVE_INFINITY="+Math.POSITIVE_INFINITY);
Number Functions
var num=Number("2");
num.toExponential()- Returns a string with a rounded number
written as exponential notation.
num.toFixed()- Returns the string of a number with a specified
number of decimals.
num.toPrecision()- String of a number written with a specified
length.
num.toString()- Returns a number as a string.
num.valueOf()- Returns a number as a number.
Math Properties
Math.E- Euler’s number.
Math.LN2- The natural logarithm of 2.
Math.LN10- Natural logarithm of 10.
Math.LOG2E- Base 2 logarithm of E.
Math.LOG10E- Base 10 logarithm of E.
Math.PI- The number PI.
Math.SQRT1_2- Square root of 1/2.
Math.SQRT2- The square root of 2.
Math Methods and Functions

Math.abs(x)- Returns the absolute (positive) value of x
Math.acos(x)- The arccosine of x, in radians
Math.asin(x)- Arcsine of x, in radians
Math.atan(x)- The arctangent of x as a numeric value
Math.atan2(y,x)- Arctangent of the quotient of its arguments
Math.ceil(x)- Value of x rounded up to its nearest integer.
Math.cos(x)- The cosine of x (x is in radians).
Math.exp(x)- Value of exponential.
Math.floor(x)- The value of x rounded down to its nearest integer.
Math.log(x)- The natural logarithm (base E) of x.
Math.max(x,y,z,...,n)- Returns the number with the highest value.
alert(Math.max(2,3,4));
Math.min(x,y,z, ...,n)- Same for the number with the lowest value.
alert(Math.min(-2,-3,-4));
Math.pow(x,y)- X to the power of y.
Math.random()- Returns a random number between 0 and 1.
Math.round(x)- The value of x rounded to its nearest integer.
Math.sin(x)- The sine of x (x is in radians).
Math.sqrt(x)- Square root of x.
Math.tan(x)- The tangent of an angle.
Errors
try- Lets you define a block of code to test for errors.
catch- Set up a block of code to execute in case of an error.
throw- Create custom error messages instead of the standard
JavaScript errors.
finally- Lets you execute code, after try and catch, regardless of the
result.
var x =Number(prompt("Enter x"));
try{
if(x == "") throw "empty"; //error cases
if(isNaN(x)) throw "not a number";
x = Number(x);
if(x > 10) throw "too high";
}catch(err) { //if there's an error
alert("Input is " + err); //output error
}finally{
alert("Done"); //executed regardless of the try / catch result
}
var ver=parseInt(ggbApplet.getVersion());
try{
if(ver== 5.0){
var A=prompt("Enter Matrix:","0,1,0,1,4; -5,4,2,6,15; -3,2,1,3,8; 2,-
1,0,-2,-5; -1,2,0,0,0");
}else{
var A = "" + ggbApplet.getValueString("Matrix");
}}catch(err){
alert("Error");
}finally{
alert("Version: "+ver);
}
Setting Dates
var d = new Date();
Date()- Creates a new date object with the current date and time
Date(2017, 5, 21, 3, 23, 10, 0)- Create a custom date object. The
numbers represent year, month, day, hour, minutes, seconds,
milliseconds. You can omit anything you want except for year and
month.
Date("2017-06-23")- Date declaration as a string Pulling Date and
Time Values.
d.getDate()- Get the day of the month as a number (1-31)

d.getDay()- The weekday as a number (0-6) Sunday-0, Monday-1,
Tuesday-2, Wednesday-3, Thursday, Friday-5, and Saturday-6.
d.getFullYear()- Year as a four-digit number (yyyy)
d.getHours()- Get the hour (0-23)
d.getMilliseconds()- The millisecond (0-999)
d.getMinutes()- Get the minute (0-59)
d.getMonth()- Month as a number (0-11)
d.getSeconds()- Get the second (0-59)
d.getTime()- Get the milliseconds since January 1, 1970
d.getUTCDate()- The day of the month in the specified date
according to universal time.
Date.now()- Returns the number of milliseconds elapsed since
January 1, 1970, 00:00:00 UTC.
Date.parse()- Parses a string representation of a date, and returns
the number of milliseconds since January 1, 1970.
const unixTimeZero = Date.parse('01 Jan 1970 00:00:00 GMT');
const javaScriptRelease = Date.parse('04 Dec 1995 00:12:00 GMT');
alert("unixTimeZero="+ unixTimeZero+
"nJavaScriptRelease="+javaScriptRelease);
d.setDate()- Set the day as a number (1-31)
d.setFullYear()- Sets the year (optionally month and day)
d.setHours()- Set the hour (0-23)
d.setMilliseconds()- Set milliseconds (0-999)
d.setMinutes()- Sets the minutes (0-59)
d.setMonth()- Set the month (0-11)
d.setSeconds()- Sets the seconds (0-59)
d.setTime()- Set the time (milliseconds since January 1, 1970)
d.setUTCDate()- Sets the day of the month for a specified date
according to universal time.
var d = new Date();
d.setFullYear(2008, 05, 15);
alert(d.getFullYear()+"-"+d.getMonth()+"-"+d.getDate());
ggbAppletMethods
var n=ggbApplet.getValue("n");
ggbApplet.setValue("a",1);
ggbApplet.evalCommand("l1={}");
ggbApplet.setListValue("l1", i, Math.random() * (vmax - vmin) +
vmin);
Notepad++ is a text and source code editor to JavaScript.
https://notepad-plus-plus.org/downloads/
Use Notepad ++ to create and edit the Geogebra JavaScript code in
Language-> J-> JavaScript and after finishing the code copy the code
in Geogebra JavaScript and compile the code in some Geogebra
object as a button to see if there are errors in the code or if the
code works.
GeoGebra Scripting
https://wiki.geogebra.org/en/Scripting
Reference:GeoGebra Apps API
https://wik.geogebra.org/en/Reference:GeoGebra_Apps_API
JavaScript Tag Search in GeoGebra Web
https://www.geogebra.org/search/tags:JavaScript
Code Snipets of Javascript in Geogebra
https://ww.geogebra.org/m/paxjwmxh

Geogebra Scripting JavaScript Notepad++ Source Code Editor JavaScript

GeoGebra JavaScript CheatSheet

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