js 获取子节点，兼容FF，IE
代码
function getFirstChild(obj) {
var result = obj.firstChild;
while (!result.tagName) {
result = result.nextSibling;
}
return result;
}
function getNextChild(obj) {
var result = obj.nextSibling;
while (!result.tagName) {
result = result.nextSibling;
}
return result;
}
var result = obj.firstChild;
while (!result.tagName) {
result = result.nextSibling;
}
return result;
}
function getNextChild(obj) {
var result = obj.nextSibling;
while (!result.tagName) {
result = result.nextSibling;
}
return result;
}
