<!DOCTYPE html>
<meta charset="utf-8">
<title>Linear gradient with transparent reference</title>
<style>
    .test {
        width: 200px;
        height: 100px;
        margin-left: 90px;
    }
    .gradient {
        background-image: linear-gradient(to left, blue 0%, blue 20%, rgba(0,0,255,0));
    }
</style>

<body>
    <p>Gradient using 'transparent'</p>
    <div id="gradient1" class="test gradient"></div>
    <br />
    <p>Gradient using rgba(0,0,255,0)</p>
    <div id="gradient2" class="test gradient"></div>
</body>