জাভাস্ক্রিপ্ট: প্রোগ্রামিং ভাষা

console.log("Hello World!"); 

function factorial(n) {if (n===0||n===1) return 1; //fact0=fact1=1     return n * factorial(n - 1)}  factorial(3); // returns 6 

function counter() { var count = 0;     return function() {return ++count}};  var closure = counter(); closure(); // returns 1 closure(); // returns 2 closure(); // returns 3 

function sum() {var x = 0;     for (var i = 0; i < arguments.length; ++i) x += arguments[i];     return x}  sum(1, 2); // returns 3 sum(1, 2, 3); // returns 6 

var counter = (function () {     var i = 0; // private property      return {   // public methods         get: function () {             alert(i);         },         set: function (value) {             i = value;         },         increment: function () {             alert(++i);         }     }; })(); // module  counter.get();       // shows 0 counter.set(6); counter.increment(); // shows 7 counter.increment(); // shows 8 

/* Finds the lowest common multiple (LCM) of two numbers */ function LCMCalculator(x, y) { // constructor function     var checkInt = function (x) { // inner function         if (x % 1 !== 0) {             throw new TypeError(x + " is not an integer"); // throw an exception         }         return x;     };     this.a = checkInt(x)     //   semicolons   ^^^^  are optional, a newline is enough     this.b = checkInt(y); } // The prototype of object instances created by a constructor is // that constructor's "prototype" property. LCMCalculator.prototype = { // object literal     constructor: LCMCalculator, // when reassigning a prototype, set the constructor property appropriately     gcd: function () { // method that calculates the greatest common divisor         // Euclidean algorithm:         var a = Math.abs(this.a), b = Math.abs(this.b), t;         if (a < b) {             // swap variables             t = b;             b = a;             a = t;         }         while (b !== 0) {             t = b;             b = a % b;             a = t;         }         // Only need to calculate GCD once, so "redefine" this method.         // (Actually not redefinition—it's defined on the instance itself,         // so that this.gcd refers to this "redefinition" instead of LCMCalculator.prototype.gcd.         // Note that this leads to a wrong result if the LCMCalculator object members "a" and/or "b" are altered afterwards.)         // Also, 'gcd' === "gcd", this['gcd'] === this.gcd         this['gcd'] = function () {             return a;         };         return a;     },     // Object property names can be specified by strings delimited by double (") or single (') quotes.     lcm : function () {         // Variable names don't collide with object properties, e.g., |lcm| is not |this.lcm|.         // not using |this.a*this.b| to avoid FP precision issues         var lcm = this.a/this.gcd()*this.b;         // Only need to calculate lcm once, so "redefine" this method.         this.lcm = function () {             return lcm;         };         return lcm;     },     toString: function () {         return "LCMCalculator: a = " + this.a + ", b = " + this.b;     } };  // একটা আউটপুট ফাংশন; এই প্রয়োগ সুধুমাত্র ওয়েব ব্রাওজারে কাজ করবে ।  function output(x) {     document.body.appendChild(document.createTextNode(x));     document.body.appendChild(document.createElement('br')); }  // Note: Array's map() and forEach() are defined in JavaScript 1.6. // They are used here to demonstrate JavaScript's inherent functional nature. [[25, 55], [21, 56], [22, 58], [28, 56]].map(function (pair) { // array literal + mapping function     return new LCMCalculator(pair[0], pair[1]); }).sort((a, b) => a.lcm() - b.lcm()) // sort with this comparative function; => is a shorthand form of a function, called "arrow function"   .forEach(printResult);  function printResult(obj) {     output(obj + ", gcd = " + obj.gcd() + ", lcm = " + obj.lcm()); }