CSS3 解决方案 - http://jsfiddle.net/UddqU/
从 - http://www.colorzilla.com/gradient-editor/生成的渐变 CSS
HTML
<div id="wrapper">
<div id="left"></div>
<div id="right"></div>
</div>
CSS:
body {background:orange;}
#left {float:left; width:25%; height:400px;
background: -moz-linear-gradient(left, rgba(230,240,163,1) 0%, rgba(255,255,255,0) 100%); /* FF3.6+ */
background: -webkit-gradient(linear, left top, right top, color-stop(0%,rgba(230,240,163,1)), color-stop(100%,rgba(255,255,255,0))); /* Chrome,Safari4+ */
background: -webkit-linear-gradient(left, rgba(230,240,163,1) 0%,rgba(255,255,255,0) 100%); /* Chrome10+,Safari5.1+ */
background: -o-linear-gradient(left, rgba(230,240,163,1) 0%,rgba(255,255,255,0) 100%); /* Opera 11.10+ */
background: -ms-linear-gradient(left, rgba(230,240,163,1) 0%,rgba(255,255,255,0) 100%); /* IE10+ */
background: linear-gradient(to right, rgba(230,240,163,1) 0%,rgba(255,255,255,0) 100%); /* W3C */
filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#e6f0a3', endColorstr='#00ffffff',GradientType=1 ); /* IE6-9 */
}
#right { float:right; width:25%; height:400px;
background: -moz-linear-gradient(left, rgba(255,255,255,0) 0%, rgba(230,240,163,1) 100%); /* FF3.6+ */
background: -webkit-gradient(linear, left top, right top, color-stop(0%,rgba(255,255,255,0)), color-stop(100%,rgba(230,240,163,1))); /* Chrome,Safari4+ */
background: -webkit-linear-gradient(left, rgba(255,255,255,0) 0%,rgba(230,240,163,1) 100%); /* Chrome10+,Safari5.1+ */
background: -o-linear-gradient(left, rgba(255,255,255,0) 0%,rgba(230,240,163,1) 100%); /* Opera 11.10+ */
background: -ms-linear-gradient(left, rgba(255,255,255,0) 0%,rgba(230,240,163,1) 100%); /* IE10+ */
background: linear-gradient(to right, rgba(255,255,255,0) 0%,rgba(230,240,163,1) 100%); /* W3C */
filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#00ffffff', endColorstr='#e6f0a3',GradientType=1 ); /* IE6-9 */
}