$.getJSON 返回值

function calculateplan(scd,pyear,stnm)
{

var result="";
var urlnew=getRootPath()+"/handler/HisSchePlan.ashx?pyear="+escape(pyear)+"&scd="+escape(scd);

$.ajaxSettings.async = false; //必须加的，若不加返回的是""

$.getJSON(urlnew,{ random: Math.random() },function(datatable){

result=calculateplan1(datatable,pyear,stnm);


});
return result;
}