To learn how to define and implement custom JavaScript exceptions, you can try to run the following code −Example                                         Click the following to see the result:                          

To catch all JavaScript unhandled exceptions, use window.error. The onerror event handler provides three pieces of information to identify the exact nature of the error −Error message − The same message that the browser would display for the given errorURL − The file in which the error occurredLine number− The line number in the given URL that caused the errorExampleYou can try to run the following code to catch unhandled exceptions −                                         Click the following to see the result:                          

Use throw statement in JavaScript, to catch custom exceptions. You can try to run the following to work with custom exceptions −Example                                             Click the following to see the result:                          

This tutorial will teach us to use the JavaScript functions as an object. However, functions, objects, and arrays are the mutable data types in JavaScript, and all mutable data types are the objects.The JavaScript object is one type of entity that contains the key-value pairs. It contains unique keys; every key has some values that can be of any type. We can use the object key to access the values of the objects.We can create a function so that it behaves like an object. Below, we have given a detailed explanation of converting the function to an object.Use JavaScript function ... Read More

In this tutorial, we will learn to assign a function to a variable in JavaScript. The function is the code block that we can reuse quickly, often just by making a function call. There are two ways to declare a function in JavaScript, one is a named function, and another is an anonymous function.Most JavaScript programmers are familiar with the name function, and users can follow the below syntax to declare the named function.function function_name() { //function body }In the above syntax, users can see that, we can create a function definition with the function keyword and following by function ... Read More

In this tutorial, we will learn how to invoke a JavaScript Function as a method. In JavaScript, the code inside a function will execute when the function is invoked. We can invoke a function in a variety of ways. One of them is using the method. The method is a property of an object that has a function value. We can define functions as object methods. This function will have a function name, a parameter (optional), and a return type (optional). It will have a "this" keyword which refers to an object. Users can follow the syntax below to declare ... Read More

In this tutorial, we will learn how to invoke a JavaScript Function as a function. Functions are a set of reusable codes that perform a specific task and may return a value. In JavaScript, functions are defined by the keyword function. A function has different parts, like a function name, parameter list, function body, and return statement. A function may not have any parameters and may also not have any return statement. In JavaScript, we also have functions with no function names, called anonymous functions. Users can follow the syntax below to declare a function. // function declaration function function_name(parameter1, ... Read More

JavaScript does not support Function Overloading. The following shows function overloading − function funcONE(x,y) { return x*y; } function funcONE(z) { return z; } The above will not show an error, but you won't get desired results. On calling, // prints 5 funcONE(5); // prints 5, not 30 funcONE(5,6); JavaScript does not support function overloading natively. If we will add functions with the same name and different arguments, it considers the last defined function.

Default ParametersThe default parameter came to handle function parameters with ease. You can easily set Default parameters to allow initializing formal parameters with default values. This is possible only if no value or undefined is passed. Example Live Demo                    // default is set to 1          function inc(val1, inc = 1) {             return val1 + inc;          }                    document.write(inc(10, 10));          document.write("");          document.write(inc(10));   ... Read More

Functions and methods are the same in JavaScript, but a method is a function, which is a property of an object.The following is an example of a function in JavaScript −function functionname(param1, param2){    // code }ExampleThe method is a function associated with an object. The following is an example of a method in JavaScript − Live Demo                    var employee = {             empname: "David",             department : "Finance",             id : 002,             details : function() {                return this.empname + " with Department " + this.department;             }          };          document.write(employee.details());           Output