some code that do something when some element appeared in your view port! Function throttle and debounce tech were used to to achieve better performance.
see demo here
open the console and see how callback were triggered.
##usage
just call the detectVisible function. it takes three parameters:
| parameter | type | example | explanation |
|---|---|---|---|
| selector | string | 'div.elem' | use document.querySelectorAll internally |
| callback | function | function(){this.classList.add('visible') | callback when the element is appeared in the viewport. 'this' refer to the element. |
| interval | number | 500 | detection interval for the elem's position. the bigger the better performance, but comes with notable delay. |
enjoy!