SCSS - Opacity

opacity.css

/// Given an opacity value, generates that value as well as a way to display that opacity value in Internet Explorer 8 and 9.
/// @access public
/// @param {Float} $opacity - Opacity
/// @example scss - Usage
///   .foo {
///     @include opacity(0.5);
///   }
/// @example css - Result
///   .foo {
///     opacity: 0.5;
///     filter: "progid:DXImageTransform.Microsoft.Alpha(Opacity=#50)";
///   }
@mixin opacity($opacity) {
    opacity: $opacity;
    -ms-filter: "progid:DXImageTransform.Microsoft.Alpha(Opacity=#{$opacity * 100})";
}