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Diffstat (limited to 'doc/development/fe_guide/performance.md')
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diff --git a/doc/development/fe_guide/performance.md b/doc/development/fe_guide/performance.md index 2ddcbe13afa..f25313d6cff 100644 --- a/doc/development/fe_guide/performance.md +++ b/doc/development/fe_guide/performance.md @@ -23,6 +23,18 @@ controlled by the server. 1. The backend code will most likely be using etags. You do not and should not check for status `304 Not Modified`. The browser will transform it for you. +### Lazy Loading + +To improve the time to first render we are using lazy loading for images. This works by setting +the actual image source on the `data-src` attribute. After the HTML is rendered and JavaScript is loaded, +the value of `data-src` will be moved to `src` automatically if the image is in the current viewport. + +* Prepare images in HTML for lazy loading by renaming the `src` attribute to `data-src` +* If you are using the Rails `image_tag` helper, all images will be lazy-loaded by default unless `lazy: false` is provided. + +If you are asynchronously adding content which contains lazy images then you need to call the function +`gl.lazyLoader.searchLazyImages()` which will search for lazy images and load them if needed. + ## Reducing Asset Footprint ### Page-specific JavaScript |