// validate year var year_str = $.trim($('#id_year').val()); var year = Number(year_str); if (isNaN(year) || year_str.length == 0) { alert('Epoch year is invalid number: ' + year_str); return(false); } if (year < 1950.0) { alert('Epoch year must not be less than 1950, not: ' + year_str); return(false); }