javascript is case-sensitive, also, you need to put your colors in quotes,for example:
<table>
<tr><td>
<table>
<tr onmouseover="this.style.backgroundColor='white'"
onmouseout="this.style.backgroundColor='blue'"><td>afdasfasfasfasfasfasfasf</td></tr>
<tr onmouseover="this.style.backgroundColor='white'"
onmouseout="this.style.backgroundColor='blue'"><td>afgsdfythjutfgfjgfhjgfjh</td></tr>
</table>
</td></tr>
<tr><td>
adfasfasfasfasfasfasdfasf
</td></tr>
</table>
<table>
<tr><td>
<table>
<tr onmouseover="this.style.backgroundColor='white'"
onmouseout="this.style.backgroundColor='blue'"><td>afdasfasfasfasfasfasfasf</td></tr>
<tr onmouseover="this.style.backgroundColor='white'"
onmouseout="this.style.backgroundColor='blue'"><td>afgsdfythjutfgfjgfhjgfjh</td></tr>
</table>
</td></tr>
<tr><td>
adfasfasfasfasfasfasdfasf
</td></tr>
</table>
function mouseOver(e){
e.style.backgroundColor = 'white';
}function mouseOut(e){
e.style.backroundColor = 'white';
}
</script>
<table>
<tr><td>
<table>
<tr onmouseover="mouseOver(this)"
onmouseout="mouseOut(this)"><td>afdasfasfasfasfasfasfasf</td></tr>
<tr onmouseover="mouseOver(this)"
onmouseout="mouseOut(this)"><td>afgsdfythjutfgfjgfhjgfjh</td></tr>
</table>
</td></tr>
<tr><td>
adfasfasfasfasfasfasdfasf
</td></tr>
</table>
<tr><td>
<table>
<tr onmouseover="this.bgColor='green'"
onmouseout="this.bgColor='blue'"><td>afdasfasfasfasfasfasfasf</td></tr>
<tr onmouseover="this.style.backgroundcolor='white'"
onmouseout="this.style.backgroundcolor='blue'"><td>afgsdfythjutfgfjgfhjgfjh</td></tr>
</table>
</td>
</tr>
<tr>
<td>
adfasfasfasfasfasfasdfasf
</td>
</tr>
</table>
onmouseout="this.style.background='';this.style.color=''" >
<td align="center"><a href="mouse.html">|-鼠标特效-|</a></td>
</tr>