add:   var startDate = jsDateToDateTime(getElementValue("event-starttime")); var endDate = jsDateToDateTime(getElementValue("event-endtime")); if (endDate.compare(startDate) == -1) { acceptButton.setAttribute("disabled", "true"); } else if (acceptButton.getAttribute("disabled")) { acceptButton.removeAttribute("disabled"); }  return; 
context: function updateAccept(){    var acceptButton = document.getElementById("calendar-event-dialog").getButton("accept");    var title = getElementValue("item-title");    if (title.length == 0)        acceptButton.setAttribute("disabled", "true");    else if (acceptButton.getAttribute("disabled"))        acceptButton.removeAttribute("disabled");}
meta: 9421	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/9421/b41c1be7a7402fb7e56149720848211ee5389cde/calendar-event-dialog.js/clean/calendar/base/content/calendar-event-dialog.js