兼容主流浏览器的CSS透明效果

.setOpacity {opacity: .75; /* 标准: Firefox 1.5 以上, Opera, Safari */filter: alpha(opacity=75); /* IE 8 以下 */-ms-filter: "alpha(opacity=75)"; /* IE 8 */-khtml-opacity: .75; /* Safari 1.x */-moz-opacity: .75; /* FF lt 1.5, Netscape */}