HTML has an <input type="range">, which is, you could argue, the simplest type of proportion slider. Wherever the thumb of that slider ends up could represent a proportion of whatever is before and whatever is after it (using the value and max attributes). Getting fancier, it’s possible to build a multi-thumb slider. But we’ve got another thing in mind today… a proportion slider with multiple thumbs, and sections that cannot overlap. Here’s what we’ll be building today: CodePen… Read article “L...