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Javascript Articles
Page 511 of 534
How to call multiple JavaScript functions in onclick event?
To call multiple JavaScript functions in onclick event, you can separate them with semicolons. This allows you to execute several functions sequentially when a single click occurs. Syntax onclick="function1(); function2(); function3()" Method 1: Using Semicolons The simplest approach is to separate multiple function calls with semicolons directly in the onclick attribute: function Display1() { document.getElementById("output").innerHTML += "Hello there!"; } ...
Read MoreHow do I call a JavaScript function on page load?
This tutorial will teach us to call a JavaScript function on page load. In many cases, while programming with HTML and JavaScript, programmers need to call a function while loading the web page or after the web page load finishes. For example, programmers need to show the welcome message to the user on page load. There are various ways to call a function on page load or after page load in JavaScript, and we will look at them one by one in this tutorial. Using the onload event in the tag ...
Read MoreWhat is the difference between a++ and ++a in JavaScript?
In JavaScript, ++a (pre-increment) and a++ (post-increment) both increase a variable by 1, but they differ in when the increment happens and what value they return. Pre-increment (++a) ++a increments the variable first, then returns the new value. The ++ operator comes before the operand. Post-increment (a++) a++ returns the current value first, then increments the variable. The ++ operator comes after the operand. Example: Basic Difference let a ...
Read MoreWhich one is better to use for a JavaScript link, "#" or "javascript:void(0)"?
When creating JavaScript links that don't navigate to another page, developers often choose between "#" and "javascript:void(0)". Both prevent default navigation, but they behave differently and have distinct use cases. Understanding the Difference The "#" anchor creates a link to the top of the current page and adds a hash to the URL, while "javascript:void(0)" executes JavaScript that returns undefined, preventing any navigation without affecting the URL. Using "#" Hash Links The hash symbol creates an anchor link that jumps to the top of the page if no element with that ID exists: ...
Read MoreHow do I split a string, breaking at a particular character in JavaScript?
JavaScript's split() method breaks a string into an array at every occurrence of a specified character or substring. This is useful for parsing data, processing text, or formatting output. Syntax string.split(separator, limit) Parameters separator: The character or string to split on limit: (Optional) Maximum number of splits to make Basic Example Let's split a string at every tilde (~) character: String Split Example ...
Read MoreHow to execute a JavaScript function when I have its name as a string?
Calling a function from a string stored in a variable can be done in multiple ways in JavaScript. The most common approaches are using the window object (for global functions), object property access, and the eval() function (though not recommended). This tutorial will guide you through different methods to execute a JavaScript function using its name as a string. Using the window Object Method The window object contains all global functions and variables. You can access any global function by treating the function name as a property of the window object. Syntax var functionName ...
Read MoreWhat is the use of JavaScript eval function?
The JavaScript eval() function executes a string as JavaScript code. While powerful, it's generally discouraged due to performance and security concerns. Syntax eval(string) Parameters string: A string representing a JavaScript expression, statement, or sequence of statements. Return Value Returns the completion value of evaluating the given code. If the completion value is empty, undefined is returned. Basic Example var a = 30; var b = 12; ...
Read MoreWhat is the (function() { } )() construct in JavaScript?
The (function() { } )() construct is an immediately invoked function expression (IIFE). It is a function that executes immediately upon creation, without needing to be called separately. Syntax (function() { // code })(); The first pair of parentheses converts the function declaration into an expression: (function(){...}) The second pair of parentheses immediately invokes that function expression. Basic Example (function() { console.log("IIFE executed immediately!"); })(); console.log("This runs after IIFE"); IIFE executed immediately! This runs after IIFE ...
Read MoreHow to check if a JavaScript function is defined?
In this tutorial, we will learn to check whether a JavaScript function is defined before calling it. If you call an undefined function, JavaScript throws a ReferenceError with the message "function is not defined." To avoid this error, you can check whether the function exists before calling it. We'll explore three different approaches to accomplish this. Using the typeof Operator The typeof operator returns the data type of a variable or function. When used with a function name, it returns 'function' if the function is defined, or 'undefined' if it's not. Syntax let isFunction ...
Read MoreWhat is "function*" in JavaScript?
The function* declaration defines a generator function that returns a Generator object. Unlike regular functions, generators can pause execution with yield and resume later, making them powerful for controlling program flow and creating iterators. Syntax Generator functions can be declared with function* in three equivalent ways: function* myFunction() {} // or function *myFunction() {} // or function*myFunction() {} How Generator Functions Work When called, a generator function doesn't execute immediately. Instead, it returns a generator object with methods like next() to control execution step by step. Basic Example ...
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