Type JavaScript Examples: Use Library: | Output Timing: s |
Quick reference to basic JavaScript commands. W3Schools Javascript Tutorial
Comment |
// this is a one-line comment /* this comment could contain linebreaks */ |
Constant | numbers 12.3 and strings "hi", "hi".charAt(0) is "h" |
Variable | start with a letter, then use letters, digits or _ (declared with var) |
Expression |
built from +, -, *, /, pow(x,y), sqrt(), PI, E, log(), floor(), ceil(), random(), sin(), cos(), tan(), atan() and constants, variables, functions |
Assignment | v = expression; |
Block |
{ statement 1; ... statement n; } |
Condition |
expression == expression or <=, <,>
, >=, !=... or !cond, cond1 && cond2, cond1 || cond2 |
if - else |
if (condition) block 1 else block 2 // optional |
for-loop |
for (var i=start; endcondition; i++) block |
while-loop |
while (condition) block |
Function |
f = function(v1, ..., vn) { statement 1; ... return expression; } |
List (array) |
a = [1,2,"hi"] a[0] is 1, a.length is 3, a.concat([4]) is [1,2,"hi",4] |
Object (hash tables) |
object = {attribute:expression, method:function} a = {x:2, y:3, s:function(){return this.x+this.y}} a.x is 3, a["x"] is 3, a.s() is 5 |
Output |
write("Hello"); writeln(" world"); |
This page is useful for experimenting with basic JavaScript and algorithms. It should work in any browser that has JavaScript enabled (including smartphones).
You can save your own local copy of this page (using Save As...), and use it even when you are not connected to the internet.