but if you have knowledge of any programming language like C, C++ or Java, it won't be very difficult for you to understand the syntax of JavaScript. It is optional to specify function parameter values while executing it. Functions are defined, or declared, with the function keyword. After the function name, open and close parentheses. apply (obj, arr) // establishing the scope as "obj" console. reduce (function (acc, num) {// func. addTwoNumbers is the function’s name, which is customizable — just like variable names. const addTwo = a => a + 2; It means that counter and Countervariables are different. JavaScript uses its own syntax to create variable, function, statements, etc. As we discussed the Nested function has parent and child functions. Next, we call a function document.write which writes a string into our HTML document. JavaScript is a case-sensitive language. log … First character must be letter, … Everything in JavaScript including variables, function names, class names, and operators are case-sensitive. It helps programmers in writing modular codes. JavaScript Function Syntax. 1. var writeLog = function ( txt, format) {2. We mainly use JavaScript to create websites web applications server-side applications using Node.js but JavaScript is not limited to these things, and it … JavaScript a function allows you to define a block of code, give it a name and then execute it as many times as you want. sum (); // => 14 JavaScript, however, allows you to omit this semicolon if each of your statements are placed on a separate line. But when formatted in a single line as follows, you must use semicolons −. bind (obj) // establishing the scope as "obj" console. log (result) // result 106 // apply const arr = [1, 2, 3] var result = add. numbers. The script tag takes two important attributes −. call (obj, 1, 2, 3) // establishing the scope as "obj" console. Once the JavaScript file is created, we need to create a simple HTML document. This statement should be the last statement in a function. A function can be defined using function keyword and can be executed using () operator. However, objects have additional features, such as a prototype chain , which ordinary associative arrays do not have. A JavaScript function is defined with the function keyword, followed by a name, followed by parentheses (). JavaScript supports both C-style and C++-style comments, Thus −. Typically, its value will be javascript. We added an optional HTML comment that surrounds our JavaScript code. The comment ends with a "//-->". Parameters: You can use spaces, tabs, and newlines freely in your program and you are free to format and indent your programs in a neat and consistent way that makes the code easy to read and understand. However, instanceOfis a valid function name. Functions are the fundamental building block of any application in JavaScript.They’re how you build up layers of abstraction, mimicking classes, information hiding, and modules.In TypeScript, while there are classes, namespaces, and modules, functions still play the key role in describing how to do things.TypeScript also adds some new capabilities to the standard JavaScript functions to make them easier to work with. Lets take a look at a regular function: function funcName(params) {return params + 2;} funcName(2); // 4This above code indicates one of the two reasons for creating arrow functions: shorter syntax.The exact same functions can be expressed as an arrow function with only one line of code: A function can take multiple parameters separated by comma. JavaScript statements don't need to be placed in parentheses or braces. JavaScript also recognizes the HTML comment opening sequence