JSFiddle - React, Tailwind, and code Playground

HTML

<br>
<h1 align="center" id="titre"><br>&nbsp;<br>&nbsp;<br>&nbsp;<br>&nbsp;<br>&nbsp;<br>&nbsp;<br><br></h1>

CSS

#titre {
    -webkit-transition: background-color 500ms linear;
    -moz-transition: background-color 500ms linear;
    -o-transition: background-color 500ms linear;
    -ms-transition: background-color 500ms linear;
    transition: background-color 500ms linear;
}

JavaScript

var coul = {"w":"FFFFFF", "c":"00FFFF", "v":"00FF00", "j":"FFFF00", "r":"FF0000", "m":"FF00FF", "b":"0000ff", "n":"000000"};
var ordr = "wcvjrmbwvrbcjmwjbvmcrwrcmvbjwmjcbrvwbmrjvcn";
var currentColor = 0;

function change_coul(){
    document.getElementById("titre").style.backgroundColor = "#"+coul[ordr[currentColor]];
    currentColor = (currentColor+1) % ordr.length;
}
 
terv = setInterval(change_coul,500);
window.onunload = function(){
    window.clearInterval(terv);
};