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Possible Duplicate: jQuery $(this) vs this I'm new to this and trying to get my concept right. There has been many instances of the use of " this " and " $(this) ". Can someone please explain the difference and in what condition that we use the two different "this"? In jQuery functions, this most often refers to the actual DOM element you're dealing with, whereas $(this) returns a jQuery object that wraps the element. In JavaScript, this always refers to the current scope. Many of jQuery's functions will set that scope to be the element you're working with. For instance $("#someElement").click

I'm trying to understand what rule for "this" that "use strict"; modifies in the below case. After reading ( http://unschooled.org/2012/03/understanding-javascript-this/ ) my best guess is that since the functon isStrictModeOn() is not "attached" to anything, this refers to null. Which is suppose to be a more sensible alternative to Javascript just attaching the this to the global object. Is that the correct interpretation of the change that "use strict" is making in this case? http://www.novogeek.com/post/ECMAScript-5-Strict-mode-support-in-browsers-What-does-this-mean.aspx function

This question already has an answer here: What does “this” mean in a nodejs module? 1 answer The code I write the following code and save it as test.js: var foo = 'I am local'; global.foo = 'I am global'; function print () { console.log(this.foo); }; print(); console.log (this.foo); I then run it in the terminal with the command node test.js and it returns: I am global undefined The question Why does it not return: I am global I am global ? Felix Kling Inside a Node module, this by design refers to module's exports object: console.log(this === exports); // true Making console.log(this.foo)

I am trying to capture onChange event of the input and calling setState with the new value, but as soon as I type in the input I get: Uncaught TypeError: Cannot read property 'setState' of undefined Even though I have called this.handleChange.bind(this) in the constructor index.js import React from 'react' import * as ReactDOM from "react-dom"; import App from './App' ReactDOM.render( <App />, document.getElementById('root') ); App.js import * as React from "react"; export default class App extends React.Component { constructor(props) { super(props) this.handleChange.bind(this) this.state =

I'm learning TypeScript and have the following class: class DetailDriver { public get driver() { return super.getEntity(); } public activate(): breeze.Promise { var id = this.driver.id(); // this refers to (class) DetailDriver return promise .then(getCertificate) .fail(somethingWrong); function getCertificate() { var id = this.driver.id(); // this refers to any return ... } } } As you can see on the above code, the first call to this refers to my class DetailDriver . That's good. The second call to this (inside getCertificate ) refers to any . That's not what I need. I need to refer to my

I have a class which creates a DOM element and has to capture all click events. Simplified code: function myClass() { this.domElement = document.createElement("canvas"); this.domElement.addEventListener("click", this.handleClick); } myClass.prototype.handleClick = function(evt) { alert("Clicked!"); // How to modify `this` object? } Now I want to modify some attributes and variables of the myClass instance in handleClick() . But this refers to the canvas object, of course. Question: How can I access this of an object in an event handler? This can be accomplished via closing over a reference to