CODEWITHSUNDEEP
javascriptjqueryfunctionundefined
Shpigford
Shpigford

Reputation: 25348

jQuery: How can I get around using an if statement to get rid of "undefined" errors

When using third-party plugins, I typically initialize them in my main application.js file.

Example:

$('.scroll').jScrollPane();

The problem is if a page loads that doesn't have the scroll class, then I get:

TypeError: Result of expression '$('.scroll').jScrollPane' [undefined] is not a function.

So to get around this, I wrap it in:

if ($(".scroll").length){
    $('.scroll').jScrollPane();
}

That remedies the problem but just seems like a hack.

Is there a "correct" way to solve this?

Upvotes: 2

Views: 712

Answers (5)

user113716
user113716

Reputation: 322502

If you're getting:

ScrollPane' [undefined] is not a function.

...it wouldn't be because the page doesn't have a .scroll element.

That sort of error occurs when the plugin (or jQuery itself) isn't loaded.

If you're reusing some code on several pages, some of which don't have that plugin, do this instead:

if ( $.fn.jScrollPane ){
    $('.scroll').jScrollPane();
}

Upvotes: 2

Oscar Godson
Oscar Godson

Reputation: 32726

As a couple others have said, that error is the jScroll's error. If it's because an element doesnt exist jQuery will return an empty array.

Its because the plugin isn't loaded. jScroll is the plugin to change the scrollbars, correct? I've had numerous issues with it. I suggest wrapping it in a 

$(window).load(function(){
    //Call it here
})

This fixed all the issues i had with it.

Upvotes: 0

Mark Baijens
Mark Baijens

Reputation: 13222

if ($('.scroll').jScrollPane()){
    $('.scroll').jScrollPane();
}

this error is prob just because an addon failed loading

Upvotes: 0

Pointy
Pointy

Reputation: 413737

Uhh ... no; jQuery doesn't work like that. A call to $("any selector") will always give you back a ready-to-use (but empty) jQuery object. I don't think that's really your problem. Can you describe more about what your page is doing?

Upvotes: 0

FatherStorm
FatherStorm

Reputation: 7183

you can use try/catch blocks...

try
  {
    $('.scroll').jScrollPane();
  }
catch(err)
  {
  //Handle or ignore errors here
  }

Upvotes: 0

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