function getByClass(oParent,sClass)
{
var aResult = [];
var aEle = oParent.getElementsByTagName("*");
for(var i = 0 ; i < aEle.length;i++)
{
fi(aEle[i].className == sClass)
{
aResult.push(aEle[i]);
}
}
return aResult;
}
oParent 是父节点