Using JavaScript console modifies outcome of script

Question

In Chrome, this fiddle prints false. However, the same code typed in the JavaScript console prints true:

a = 1;
var a = 2;
console.log(delete a);

Why do I get different results depending on whether or not I'm using the Chrome console?

Pasting this into console gives SyntaxError: Unexpected token ILLEGAL, Chrome (Linux) — Paul S.
– Paul S., Commented Sep 14, 2012 at 23:48

Matt Ball · Accepted Answer · 2012-09-14 23:56:04Z

1

Because the Chrome console runs inside an eval construct or something similar, rather than running in the global scope.

There is a lot of discussion about the delete operator here on StackOverflow. A search for [javascript] delete will help answer other questions that come up.

edited Sep 14, 2012 at 23:56

Matt Ball

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answered Sep 14, 2012 at 23:48

Jeremy J Starcher

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Comments

Kyle Trauberman · Accepted Answer · 2012-09-15 00:53:16Z

0

var defined variables can not be deleted.

edited Sep 15, 2012 at 0:53

Kyle Trauberman

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answered Sep 15, 2012 at 0:47

yapingchen

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1 Comment

Ethan Brown Over a year ago

Apparently you can in the Chrome console, though, which is the OPs question. I tried it myself; he's right.

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