I want to validate custom modal dialog form and if its not ok, prevent form from closing. For this purpose, I attached to X-close-dialog-button. Problem is to prevent it's default behavior.
function fValidateBeforeClose(event) {
event.stopImmediatePropagation(); // Not working
}
function fAddOnCloseHandler() {
var oCloseButton = jQuery("a[id^='DlgClose']", parent.document);
oCloseButton.on( "click", function (event) { fValidateBeforeClose(event)} );
}
_spBodyOnLoadFunctionNames.push( ExecuteOrDelayUntilScriptLoaded(fAddOnCloseHandler, "SP.js") );