const alphaToHex = (alpha => {
if (alpha > 1 || alpha < 0 || isNaN(alpha)) {
throw new Error('The argument must be a number between 0 and 1');
}
return Math.ceil(255 * alpha).toString(16).toUpperCase();
})
console.log(alphaToHex(0.45));
.green{
background: #82bc00 /*actual green*/
}
.subgreen{
background: #82bc0070 /*green with little transparency*/
}
.greenparency{
background: #82bc0040 /*green with much transparency*/
}
.transparency{
background: #82bc0000 /*full transparency over green*/
}
<div class="green"> green background color </div>
<div class="subgreen"> green background color </div>
<div class="greenparency"> green background color </div>
<div class="transparency"> green background color </div>