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Developers console saying function is "undefined" but the function runs fine

  • 5 replies
  • 1 has this problem
  • 173 views
  • Last reply by finitarry

Mythical
Mythical
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I'm a web developer, and I've been working on creating a site ( http://mythicalslab.x10host.com/ ). On the site I have some javascript that handles displaying a div with a loading animation on it. In script html tags, I have two function defined, hideLoading() and showLoading() which respectively show and hide the loading animation.

If I go into the Javascript console in Firefox, and either type hideLoading() or showLoading(), the console says "undefined", but it still runs the function correctly.

If you want to check this put for yourself, go to my homepage ( http://mythicalslab.x10host.com/ ) and type showLoading() in the dev console, and you'll see it will run the function and show the loading animation, while saying it is undefined.

I'm a web developer, and I've been working on creating a site ( http://mythicalslab.x10host.com/ ). On the site I have some javascript that handles displaying a div with a loading animation on it. In script html tags, I have two function defined, hideLoading() and showLoading() which respectively show and hide the loading animation. If I go into the Javascript console in Firefox, and either type hideLoading() or showLoading(), the console says "undefined", but it still runs the function correctly. If you want to check this put for yourself, go to my homepage ( http://mythicalslab.x10host.com/ ) and type showLoading() in the dev console, and you'll see it will run the function and show the loading animation, while saying it is undefined.

Modified by Mythical

Chosen solution

Undefined is about the return value of a function call. You only see something useful when a function returns value. If nothing is returned then you see undefined.

  • (function (){return("OK")})()
  • (function (){})()
Read this answer in context 👍 1

All Replies (5)

finitarry
finitarry
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http://mythicalslab.x10host.com/ I do not see any textbox on that page at all. I accessed the page with two completely different browsers. Where is this dev console?

cor-el
cor-el
  • Top 25 Contributor
  • Moderator
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Chosen Solution

Undefined is about the return value of a function call. You only see something useful when a function returns value. If nothing is returned then you see undefined.

  • (function (){return("OK")})()
  • (function (){})()

Modified by cor-el

Mythical
Mythical Question owner
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cor-el said

Undefined is about the return value of a function call. You only see something useful when a function returns value. If nothing is returned then you see undefined.
  • (function (){return("OK")})()
  • (function (){})()

Oooh, okay, I thought it was saying whether the console ran the function correctly or not.

Mythical
Mythical Question owner
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finitarry said

http://mythicalslab.x10host.com/ I do not see any textbox on that page at all. I accessed the page with two completely different browsers. Where is this dev console?

I'm talking about the developers console built-into Firefox in the developer tools window.

finitarry
finitarry
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Right, I forgot about that. I do not use that very often. I see a lot of complaints about graphical settings such as: Expected declaration but found '/'.