各浏览器都支持的渐变
filter:alpha(opacity=100 finishopacity=50 style=1 startx=0,starty=0,finishx=0,finishy=150) progid:DXImageTransform.Microsoft.gradient(startcolorstr=red,endcolorstr=blue,gradientType=0);
-ms-filter:alpha(opacity=100 finishopacity=50 style=1 startx=0,starty=0,finishx=0,finishy=150) progid:DXImageTransform.Microsoft.gradient(startcolorstr=red,endcolorstr=blue,gradientType=0);/*IE8*/
background:red; /* 一些不支持背景渐变的浏览器 */
background:-moz-linear-gradient(top, red, rgba(0, 0, 255, 0.5));
background:-webkit-gradient(linear, 0 0, 0 bottom, from(#ff0000), to(rgba(0, 0, 255, 0.5)));
-ms-filter:alpha(opacity=100 finishopacity=50 style=1 startx=0,starty=0,finishx=0,finishy=150) progid:DXImageTransform.Microsoft.gradient(startcolorstr=red,endcolorstr=blue,gradientType=0);/*IE8*/
background:red; /* 一些不支持背景渐变的浏览器 */
background:-moz-linear-gradient(top, red, rgba(0, 0, 255, 0.5));
background:-webkit-gradient(linear, 0 0, 0 bottom, from(#ff0000), to(rgba(0, 0, 255, 0.5)));
