用css实现网页背景渐变的代码如下：

一、从上往下渐变

Example Source Code:
body{
FILTER: progid:DXImageTransform.Microsoft.Gradient(gradientType=0,startColorStr=#ffffff,endColorStr=#000000);
}

二、从左上至右下渐变

Example Source Code:
body{
FILTER: Alpha( style=1,opacity=25,finishOpacity=100,
startX=50,finishX= 100,startY=50,finishY=100);
background-color: skyblue;
}

三、从左往右渐变

Example Source Code:
body{
FILTER: progid:DXImageTransform.Microsoft.Gradient(gradientType=1,startColorStr=#ffffff,endColorStr=#000000);
}

四、从上往下渐变

Example Source Code:
style="filter:progid:DXImageTransform.microsoft.gradient(gradienttype=0,startColorStr=blue,endColorStr=white);"