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Asynchronous Script Loading Callback

http://jsfiddle.net/JamesKyle/HQDu6/

I've created a short function based on Mathias Bynens Optimization of the Google Analytics asynchronous script that goes as following:

function async(src) {
 var d = document, t = 'script',
 o = d.createElement(t),
 s = d.getElementsByTagName(t)[0];
 o.src = '//' + src;
 s.parentNode.insertBefore(o, s);
}

This works great and I've already started using it for several different scripts

// Crazy Egg
async('dnn506yrbagrg.cloudfront.net/pages/scripts/XXXXX/XXXXX.js?' + Math.floor(new Date().getTime() / 3600000));
// User Voice
var uvOptions = {};
async('widget.uservoice.com/XXXXX.js');
// Google Analytics
var _gaq = [['_setAccount', 'UA-XXXXX-XX'], ['_setDomainName', 'coachup.com'], ['_trackPageview']];
async('google-analytics.com/ga.js');
// Stripe
async('js.stripe.com/v1');

The problem comes when I encounter a script that needs to be called after it's loaded:

// Snap Engage
async('snapabug.appspot.com/snapabug.js');
SnapABug.init('XXXXX-XXXXX-XXXXX-XXXXX-XXXXX');

So I figured I'd turn this into a callback function that would be used as so:

async('snapabug.appspot.com/snapabug.js', function() {
 SnapABug.init('XXXXX-XXXXX-XXXXX-XXXXX-XXXXX');
});

I did not expect that this would be difficult for me to do but it has turned out that way.

My question is what is the most efficient way to add a callback without overcomplicating the code.

See the jsfiddle: http://jsfiddle.net/JamesKyle/HQDu6/

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2

Small improvement: If you use script.addEventListener('load', callback,{ once: true }); then the listener will be cleared automatically after the load event has fired.

Humppakäräjät
– Humppakäräjät

2023年01月22日 17:39:29 +00:00
Commented Jan 22, 2023 at 17:39

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Asynchronous Script Loading Callback

My question is what is the most efficient way to add a callback without overcomplicating the code.

Answer*