**[ This description is mirrored from README.md at [github.com/moritonal/intersection-observer-element](https://github.com//moritonal/intersection-observer-element/blob/v1.0.8/README.md) on 2019-05-22 ]** # \ [](https://www.webcomponents.org/element/Glitch0011/intersection-observer-element) Set's `visible` to true when the viewport crosses the set threshold of the element. ```

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``` ## Install ``` bower install --save intersection-observer-element ``` ## Options ### thresholds Default: [0.0, 0.25, 0.5, 0.75, 1.0] The percentages across the element where an event is raised that the intersection has changed. ### visibleLimit Default: 0.5 The percentage whereby the element swaps between visible or not. ### rootMargin Default: 0px Directly passed into IntersectionObserver class as rootMargin ## Polyfills This element uses the Intersection Observer Api, which whilst most modern browsers currently support, it is missing from iOS Safari. More detailed information can be found at [CanIUse](https://caniuse.com/#search=intersection). If you wish to support multiple browsers it's recommended you also use one of the Polyfills from [here](https://github.com/w3c/IntersectionObserver/tree/gh-pages/polyfill). ## Developing ### Install the Polymer-CLI First, make sure you have the [Polymer CLI](https://www.npmjs.com/package/polymer-cli) installed. Then run `polymer serve` to serve your element locally. ### Viewing Your Element ``` $ polymer serve ``` ### Running Tests ``` $ polymer test ``` Your application is already set up to be tested via [web-component-tester](https://github.com/Polymer/web-component-tester). Run `polymer test` to run your application's test suite locally.