tips存CSS实现，支持IE7+、Chrome、Firefox、Opera

tips-for-css.css

a .tips_hover {
	color:#333;
	line-height:18px;
        vertical-align:middle;
	text-shadow:#ffffff 0 1px 0;
        text-align: left;
        padding:7px 14px;
        width: 300px;
        position: relative;
        top: -999px; 
        right: 340px;
        border:1px solid #919191;
        background:#fff;
	background:-webkit-gradient(linear,left top,left bottom,from(#ffffff),to(#e4e5f0));
	background:-webkit-linear-gradient(top,#ffffff,#e4e5f0);
	background:-moz-linear-gradient(top,#ffffff,#e4e5f0);
	background:-ms-linear-gradient(top,#ffffff,#e4e5f0);
	background:-o-linear-gradient(top,#ffffff,#e4e5f0);
	background-image:-ms-linear-gradient(top,#ffffff 0%,#e4e5f0 100%);
	border-radius:4px;
	box-shadow:rgba(0,0,0,0.3) 0 1px 3px,inset rgba(255,255,255,0.4) 0 1px 0;
	opacity:0;
	filter:alpha(opacity=0); /* for IE8 and earlier */
	-webkit-transition:opacity .3s ease,top .3s ease;
	-moz-transition:opacity .3s ease,top .3s ease;
	-o-transition:opacity .3s ease,top .3s ease;
	transition:opacity .3s ease,top .3s ease;
}
a:hover .tips_hover{
	top: 10px;
	opacity:1 ;
	filter:alpha(opacity=100); /* for IE8 and earlier */
	-webkit-transition:opacity .3s ease,top .3s ease;
	-moz-transition:opacity .3s ease,top .3s ease;
	-o-transition:opacity .3s ease,top .3s ease;
	transition:opacity .3s ease,top .3s ease;
}