JS+CSS设置img在DIV中只显示Img垂直居中的部分

<div style="width: 190px; height: 100px; overflow: hidden;">
<img src="http://beijing.timeoutcn.com/UserFiles/Images/2013-10-21/20131021104840077cover-22-1.jpg" width="190px" style="vertical-align: middle;"
onload="this.style.marginTop = (parseInt(this.parentNode.style.height) - this.height)/2 + 'px';this.style.marginLeft = (parseInt(this.parentNode.style.width) - this.width) /2 + 'px'" />
</div>