The following class should be applied to an element to make it opaque:

.opaque {
	opacity: .5;
	filter: alpha(opacity=50);
	-moz-opacity: .5;


  • opacity is for Safari
  • filter is for IE
  • -moz-opacity is for Mozilla

This specifies an opacity of 50% i.e. semi-transparent where 100 is not transparent and 0 is completely transparent. Note that the width OR height of the opaque element needs to be specified for opacity to work in IE.