What the difference between window.setTimeout() and setTimeout()?

javascript settimeout
user3073240 picture user3073240 · Dec 6, 2013 · Viewed 13.9k times · Source

I would like to know what the difference is between 

window.setTimeout(myFancyFunciton, 1000);

and 

setTimeout(myFancyFunciton, 1000);

Both seem to do the exact same thing. When should you use one or the other?

Answer

Oswald picture Oswald · Dec 6, 2013

JavaScript runs in an environment that is defined by a global object. Methods of the global object can be called without explicitly refering to the object (i.e. without the obj.function() notation).

When you run JavaScript inside the browser, the global object is provided by the Document Object Model (DOM). The global object of the DOM has a method setTimeout(). That's why you can call setTimeout().

The DOM specifies that the global object has a property named window, which is a reference back to the global object. That's why you can call window.setTimeout() and (by transitivity) window.window.setTimeout(), window.window.window.setTimeout(), and (you guessed it) window.window.window.window.window.window.window.window.window.setTimeout(). It's all the same method of the same object.

Related questions

How can I pass a parameter to a setTimeout() callback?

I have some JavaScript code that looks like: function statechangedPostQuestion() { //alert("statechangedPostQuestion"); if (xmlhttp.readyState==4) { var topicId = xmlhttp.responseText; setTimeout("postinsql(topicId)",4000); } } function postinsql(topicId) { //alert(topicId); } I get an error that topicId is not defined Everything was working before …

Read More
Execute script after specific delay using JavaScript

Is there any JavaScript method similar to the jQuery delay() or wait() (to delay the execution of a script for a specific amount of time)?

Read More
Difference between setTimeout with and without quotes and parentheses

I am learning JavaScript and I have learned recently about JavaScript timing events. When I learned about setTimeout at W3Schools, I noticed a strange figure which I didn’t run into before. They are using double quotes and then …

Read More