The isNan() function returns true if the variable value is not a number otherwise returns false. It internally checks whether the specified value is an illegal number or not. Syntax: isNaN(value) Parameters: value: It represents the value to be checked for not a number. Returns: It returns true if the value is an illegal number … Read more
By Object() constructor: var obj = new Object(); By Object.create() method: Object.create: Will return a new object with properties of prototypeObject. var obj = Object.create(prototypeObject); By brackets: It is the same as Object.create() method with a null parameter. var obj = {}; By function constructor: var MySite = function(website) { this.website = website; } var … Read more
The src attribute of the script tag is used to add or include external JavaScript files into any number of HTML files. It increases the code reusability. Syntax: <script type=”text/javascript” src=”external.js”></script> First, create a JavaScript file and then save the file with the .js extension. After that, we can use the src attribute of the … Read more
Yes. JavaScript is a case-sensitive language. Related topics: What is JavaScript? What are the advantages of JavaScript? What are the disadvantages of JavaScript? Is JavaScript a case-sensitive language? How to use external JavaScript file? How to create javascript object? How to add method to javascript object? What does the isNaN() function? What is the difference … Read more
1. Security: As JavaScript executes on the client side it can be used to exploit the application. 2. UI inconsistency: Sometimes JavaScript is interpreted differently by different browsers resulting in the inconsistent UI. See more at Javascript overview. Related topics: What is JavaScript? What are the advantages of JavaScript? What are the disadvantages of JavaScript? Is JavaScript … Read more
JavaScript advantages Fast speed: JavaScript is executed on the client side that’s why it is very fast. Easy to learn: JavaScript is easy to learn. Anyone who has basic knowledge of programming can easily learn JavaScript. Versatility: It refers to lots of skills. It can be used in a wide range of applications. Browser Compatible: JavaScript supports … Read more
The Javascript confirmation dialog box is used to display a message to the user to confirm something. Note: Confirmation dialog box gives two buttons “OK” and “Cancel”. The confirm() method returns true if the OK button is clicked else returns false. Example: <!DOCTYPE html> <html> <body> <script> function getConfirmation(){ var retVal = confirm(“Do you want … Read more
The Javascript alert dialog box is used to display a warning message to the users. Note: Alert dialog box gives one button “OK”. Example: <!DOCTYPE html> <html> <body> <script> function giveWarning() { alert(“Warning message.”); document.write (“Warning message.”); } </script> <p>Click Submit button and see result.</p> <form> <input type=”button” onclick=”giveWarning()” value=”Submit” /> </form> </body> </html>
Event: The happening of something is known as an event. JavaScript event: JavaScript uses DOM events for interacting with HTML when a webpage is manipulated by a user or browser. Clicking a button, keypress, etc. are examples of an event. Example: <!DOCTYPE html> <html> <body> <script> function sayHello() { alert(“Onclick event.”) } </script> <p>Click Say … Read more
A JavaScript Math object provides no. of properties and methods for performing mathematical operations. Math is not a constructor and all the properties and methods of Math are static. Example: <script> var num = Math.random(); var squarRoot = Math.sqrt(num ) ; document.write(“Random Number: ” + num + “</br>”); document.write(“Square root: ” + squarRoot ); </script> … Read more