JSFiddle - React, Tailwind, and code Playground

HTML

Heatmap

<p id="multi"> </p>

JavaScript

var newVal = 100;

function colorMe(v){
    return "rgb(" + conv(v) + "," + (255-conv(v)) + ",0)";
}

function conv(x){
    return Math.floor((x - 100) / 1700 * 255);
}

$("#multi").css("background-color", colorMe(newVal));