Answer by GibboK for JavaScript global event mechanism

// display error messages for a page, but never more than 3 errorswindow.onerror = function(msg, url, line) {if (onerror.num++< onerror.max) {alert("ERROR: "+ msg +"\n"+ url +":"+ line);return true;}}onerror.max = 3;onerror.num = 0;