求助，div设置为absolute定位，高度为父元素的100%，但在IE8下不生效

直接上代码，在jsfiddle下运行正常，但在IE运行不正常

<div class="menu">
    <div class="menu-bar"></div>
    <div class="menu-body">
        <h3>Programs</h3>
        <h3>Documents</h3>
        <h3>Run</h3>
    </div>
</div>  
.menu {
    border: 1px solid black;
    position: relative;
    width: 200px
}

.menu-bar {
    background-color: gray;
    position: absolute;
    left: 0;
    top: 0;
    width: 30px;
    height: 100%;
}

.menu-body h3 {
    border: 1px solid blue;
    line-height: 30px;
    vertical-align: middle;
    margin: 0 0 0 30px;
}