解决方案
把ajax改为异步，用deferred
代码
function renderChildData(d) {
var params = '&' + d.hasNewChild + '&baseTime=' + getparams().baseTime + '&period=' + getparams().period;
var childTreeData = null;
var deferred = $.Deferred();
var request = $.ajax({
url: api.childTree + params,
type: 'GET',
data: {},
beforeSend: function () {
$('#childLoading').html(common.loadingImg);
},
dataType: 'json'
});
request.done(function (json) {
$('#childLoading').empty();
if (json.success) {
var data = json.data;
childTreeData = mapTreeData(data);
deferred.resolve(childTreeData);
} else {
nuit.msg({type: 'warn', msg: json.msg, closable: true, timeoutclose: true});
deferred.reject(childTreeData);
}
return childTreeData;
});
request.fail(function () {
$('#childLoading').empty();
deferred.reject(childTreeData);
});
return deferred;
}
renderChildData(d).then(function (child) {
// 这里的child 就是renderChildData 返回的childTreeData
}