Validation to check end date should not be greater than start date+1 year ServiceNow

 function onChange(control, oldValue, newValue, isLoading) {
    if (isLoading || newValue == '') {
        return;
    }
if(g_form.getValue("request_type")=="1" ||  g_form.getValue("request_type")=="Rehire / Re-Enable User")
{
         if (new Date(g_form.getValue("start_date")) > new Date(g_form.getValue("end_date"))) {
        g_form.clearValue("end_date");
        alert("End Date should not exceed more than one year from start date");
    }
    var getDate = g_form.getValue('start_date'); //Choose the field to add time from
    if(g_form.getValue("end_date")!="")
    {
var addtime = 365; //The amount of time to add
var addtype = 'day'; //The time type. Can be second, minute, hour, day, week, month, year.
 var ajax = new GlideAjax('ClientDateTimeUtils');
ajax.addParam('sysparm_name', 'addDateTimeAmount');
ajax.addParam('sysparm_fdt', getDate);
ajax.addParam('sysparm_addtime', addtime);
ajax.addParam('sysparm_addtype', addtype);
ajax.getXMLAnswer(doSomething);
    }
}
function doSomething(answer){
    var ans=answer.split(" ");
    if (new Date(g_form.getValue("end_date")) > new Date(ans[0])) {
        g_form.clearValue("end_date");
        alert("End Date should not exceed more than one year from start date");
    }
}