Comments on: An Introduction to JavaScript’s “this”

By: Anonymous

Anonymous — Thu, 04 Feb 2010 10:36:23 +0000

Caffeinated Simpleton » Blog Archive » An Introduction to JavaScript’s “this”…

JavaScript is an amazing little language, but it’s got some quirks that turn a lot of people off. One of those quirks is this, and how it’…

By: uberVU - social comments

uberVU - social comments — Wed, 03 Feb 2010 23:07:01 +0000

Social comments and analytics for this post…

This post was mentioned on Hackernews by mhansen: The way I remember it: this is whatever is before the dot when you call the function.E.g. for car.drive(); in the drive function, any reference to ‘this’ will get ‘car’. If the function is called on…

By: vilcans

vilcans — Tue, 29 Sep 2009 10:40:23 +0000

Good article. I have been very confused by “this”.

By: Olivier Mengué

Olivier Mengué — Tue, 29 Sep 2009 06:24:55 +0000

Variable scope in JavaScript is function. There is no block scope.
Defining variable 'a' with a 'var' statement inside the loop is just misleading. JavaScript is not Java.
So the two version do the same.

Also you didn't test your code at all.. Else you would have seen that alert is not called by setTimeOut but instead inside the loop.
You should have written this:
setTimeout(function { alert(i) }, 500);

By: hugobryn

hugobryn — Mon, 28 Sep 2009 20:11:13 +0000

There is a bit more to the setTimeout() function to be totally clear:

1) setTimeout(myObj.myFunc, 1000) - this set to global window object

2) setTimeout(function() { myObj.myFunc() }, 1000) - this set to myObj as we want it.

But you can also pass a string to setTimeout and basically setTimeout() becomes a sort of eval:

3) setTimeout('myObj.myFunc()', 1000) - this set to myObj

Number 2 is the best way to go though.