css hexadecimal color transparent code example
Example 1: background opacity css hex
background-color: #ff000088; <--- the 88 is the alpha
background-color: #ff0000 50%;
Example 2: javascript add alpha to hex
function addAlpha(color: string, opacity: number): string {
// coerce values so ti is between 0 and 1.
const _opacity = Math.round(Math.min(Math.max(opacity || 1, 0), 1) * 255);
return color + _opacity.toString(16).toUpperCase();
}
addAlpha('FF0000', 1); // returns 'FF0000FF'
addAlpha('FF0000', 0.5); // returns 'FF000080'