code: function( opacity )
  		{
  			if ( CKEDITOR.env.ie )
  			{
  				opacity = Math.round( opacity * 100 );
  				this.setStyle( 'filter', opacity >= 100 ? '' : 'progid:DXImageTransform.Microsoft.Alpha(opacity=' + opacity + ')' );
  			}
  			else
  				this.setStyle( 'opacity', opacity );
  		}
docs: Sets the opacity of an element.
  @param {Number} opacity A number within the range [0.0, 1.0].
  @example
  var element = CKEDITOR.dom.element.getById( 'myElement' );
  <b>element.setOpacity( 0.75 )</b>;