Features / JavaScript optimization
Your page should
respond.
Not just appear.
A visible button is not much use if the browser is too busy to answer a tap. Airlift moves eligible scripts out of the first load, with exclusions for the ones that need to run.
Get Airlift freeOptimize delivery. Keep your original theme and plugin files.
Not every script needs
to run at the start.
Chat, tracking and other extras can compete with the content a visitor came to see. Airlift changes their timing—not what your plugins are there to do.
Defer
Let the page be read first.
Eligible scripts execute after the browser has read the HTML, instead of repeatedly stopping it along the way.
Delay
Let eligible extras wait.
Selected scripts wait for interaction once the delay runtime is ready. A timed trigger can also be used when configured.
Exclude
Keep essentials outside delay.
Scripts needed for consent, product options or payment can be excluded. The right exclusions depend on your site.
The widget depends on more than one file
A carousel still needs
the code that makes it move.
Page builders load code that loads more code. Optimizing the first file alone can miss the dependencies behind your carousel, popup or form.
Keep dependencies in order.
Airlift’s delayed-script runtime preserves ordering within its execution groups and restores scripts at their original positions.
Deliver the events scripts expect.
Where the full delay runtime applies, load-event replay helps initialize scripts that start after the original page-load events.
Use builder-specific safeguards.
Elementor and Pro have dependency handling. A Divi compatibility guard can disable bundling. Special builder handling is included on paid plans.
How does Airlift check for new JavaScript errors?
Where automatic level selection is enabled, Airlift compares homepage console errors in a mobile browser before and after optimization. It can choose a gentler setting with less delay or bundling. This is configuration-dependent, not a test of every page, form or checkout.
Keep the important interactions working
The enquiry matters
more than the score.
A fast first view is only useful if the visitor can finish what they came to do.
Keep time-sensitive scripts outside delay. Check your forms, consent banner, product options and checkout after optimization—not just the homepage screenshot.
Tracking has a timing requirement too.
Delayed analytics or pixels may miss visitors who leave before they run. Review attribution and consent requirements, and exclude scripts that need their original timing.
Timing is only part of the work
Fewer requests.
Smaller eligible files.
Minify supported site scripts.
Remove unnecessary formatting from eligible files. If minification fails or makes a file larger, keep the original.
Avoid requests where it makes sense.
Eligible small scripts can be embedded, and supported core or builder groups can be bundled. Original files are not edited.
Prepare delayed downloads.
Background prefetching can prepare delayed files before they run. It does not execute JavaScript off the main thread or guarantee an instant response.
Added a plugin?
Check the new page, too.
A new booking widget or marketing tag changes the work your page does. Subsequent optimization runs pick up changed scripts. Paid plans include scheduled re-optimization; Free supports manual runs within its allowance.
Compare available before-and-after results in Airlift, then try the journeys that matter to your business on desktop and mobile.
Compare plansQuestions about JavaScript optimization
No. Airlift changes when scripts run and how eligible files are delivered. It does not remove unused functions or perform tree-shaking. Delayed code still has to execute later, so delay is not the same as reducing the total amount of work.
Defer lets the browser continue reading the HTML before executing a script. Delay holds eligible scripts until a later trigger, typically interaction after the runtime is ready. An optional timer can also trigger them when configured. These are different treatments, not interchangeable names.
Important scripts can be excluded from delay. Correct exclusions depend on your site and its dependencies; Airlift does not automatically identify every critical interaction. Test forms, consent behavior, product options and checkout after optimization. A better speed score is not a substitute for checking these journeys.
Yes. A visitor who leaves before delayed analytics or pixels run may not be counted. Review your tracking and consent requirements, and keep time-sensitive scripts outside delay where needed. Do not assume attribution will remain unchanged.
Airlift has specific handling for eligible Elementor and Elementor Pro bundles. It can include widget chunks observed in browser requests and adjust the loader to avoid fetching those chunks again. There is also a Divi compatibility guard that disables bundling when its jQuery shim is detected. This is not a guarantee for every builder, widget or configuration. Special builder handling is listed on paid plans.
Where automatic JavaScript level selection is enabled, Airlift compares homepage console errors in a mobile browser before and after optimization and can choose a gentler setting. That check is configuration-dependent and does not test every interaction or page. Some failures do not produce console errors, so important journeys still need testing.
Third-party scripts are only deferred or delayed by this layer. They are not minified, bundled or re-hosted. Minification and optimized copies apply to eligible site scripts; supported small scripts and bundle groups can reduce requests.
No. Airlift serves optimized copies and rewrites eligible page output. Original theme and plugin files remain unchanged. Minification and upload failures have fallbacks, and JavaScript optimization can be disabled independently of other layers.
A page people can see.
And actually use.
Reduce competing script work without editing your original theme or plugin files.