50projects50days/custom-range-slider/script.js
2020-10-23 18:59:52 -04:00

27 lines
961 B
JavaScript

const range = document.getElementById('range')
range.addEventListener('input', (e) => {
const value = +e.target.value
const label = e.target.nextElementSibling
const range_width = getComputedStyle(e.target).getPropertyValue('width')
const label_width = getComputedStyle(label).getPropertyValue('width')
const num_width = +range_width.substring(0, range_width.length - 2)
const num_label_width = +label_width.substring(0, label_width.length - 2)
const max = +e.target.max
const min = +e.target.min
const left = value * (num_width / max) - num_label_width / 2 + scale(value, min, max, 10, -10)
label.style.left = `${left}px`
label.innerHTML = value
})
// https://stackoverflow.com/questions/10756313/javascript-jquery-map-a-range-of-numbers-to-another-range-of-numbers
const scale = (num, in_min, in_max, out_min, out_max) => {
return (num - in_min) * (out_max - out_min) / (in_max - in_min) + out_min;
}