Function is not defined in javascript

Question

can you help me?

I'm using a script in one file to call other function in another file, but I'm getting function is not defined. So I've start searching to fix this way but I didn't get any positive results. Check my code below:

index.html

$(document).ready(function(){
    setInterval(function(){
        lAs = new loadAsync();
    }, 900);
});

js/plugins.js

function window.loadAsync() {
    $(".loadAsync").each(function(index, element){
        $(element).attr("src", $(element).attr("data-src"));
    });
}

So, what should I do to fix this problem? Thank you.

@edit:

<script src="js/plugins.js"></script>

I've already wrote this in index.html

What is this function window.loadAsync() way of declaring functions ? You should be getting a SyntaxError. — doubleOrt
– doubleOrt, Commented May 18, 2018 at 22:54
I saw it on another thread in stackoverflow, but with it or not, the error persists: Uncaught ReferenceError: loadAsync is not defined — Strepk
– Strepk, Commented May 18, 2018 at 22:57
If it's still not defined, then there's some problem that isn't represented in your question. — user2437417
– user2437417, Commented May 18, 2018 at 23:10

user2437417 · Accepted Answer · 2018-05-18 23:04:00Z

3

First, your syntax is wrong. An identifier may not have a . in it. Just use loadAsync and it'll be global unless you've nested it in another scope.

You can also make the jQuery more efficient by calling .attr() with a callback instead of using .each().

Finally, it seems unlikely that you actually want to use new to invoke the function. I changed the code below to simply pass it as the callback to setInterval. I also declared the lAs variable properly.

function loadAsync() {
    $(".loadAsync").attr("src", function(){
        return $(this).attr("data-src");
    });
}

var lAs;
$(document).ready(function(){
    lAs = setInterval(loadAsync, 900);
});

And of course all this can be done easily without jQuery.

function loadAsync() {
  for (const el of document.querySelectorAll(".loadAsync")) {
    el.src = el.dataset.src;
  }
}

var lAs;
document.addEventListener("DOMContentLoaded", function(){
    lAs = setInterval(loadAsync, 900);
});

answered May 18, 2018 at 23:04

user2437417

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6 Comments

doubleOrt Over a year ago

Downvoted because you most likely downvoted my answer while essentially repeating the same thing in yours. If the reasoning is different, please do inform me and I will remove my downvote.

user2437417 Over a year ago

Thanks. IMO, things would be so much better if they just allowed votes to be public.

doubleOrt Over a year ago

@Crazy_Train Yep, downvotes certainly should be harder, I bet that there are certain people who don't even view question details and just downvote based on bad titles, therefore throwing half the new questions into an abyss, but I hear that they are making the site from friendly towards newcomers.

Strepk Over a year ago

@doubleOrt also I didn't downvoted you too, I haven't level to perform this action.

Strepk Over a year ago

@CrazyTrain I'm getting this warning/error now: prntscr.com/jjqqur

|

doubleOrt · Accepted Answer · 2018-05-18 23:01:32Z

0

First of all, function window.whatever() {} is wrong (could you include the link of the SO thread where you saw that being used ?).

Since you are getting an error even without that, please make sure that:
1. loadAsync is declared in the global scope in the plugins file.
2. You are including js/plugins.js correctly. Go on and insert foo bar; in js/plugins.js and then check if you get a SyntaxError (while including it before the other JS file), if you don't, you are not correctly including it.

answered May 18, 2018 at 23:01

doubleOrt

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1 Comment

Strepk Over a year ago

I saw yesterday, I don't have the link right now. Sorry.

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