javascript中取table或td的背景url(在线等)
<html>
<head>
<script>
function imgshow()
{
alert(test.style.backGround)
}
</script>
</head>
<body>
<table width="300" height="300" background='images/蘑菇.jpg' id='test' onClick="imgshow();">
<tr>
<td></td>
</tr>
</table>
</body>
</html>
我怎么取到这个字符串'images/蘑菇.jpg',
我用backgroundImage,backgroundimg,backgroundImage.src,backgroundImage.url
等都不行,郁闷中,请麻烦解答,谢谢