function isAlien(a){ return isObject(a) && typeof a.constructor != 'function';}
function isArray(a){ return isObject(a) && a.constructor == Array;}
function isBoolean(a){ return typeof a == 'boolean';}
function isFunction(a){ return typeof a == 'function';}
function isNull(a){ return typeof a == 'object' && !a;}
function isNumber(a){ return typeof a == 'number' && isFinite(a);}
function isInt(a){ return ((a % 1) == 0) ? true : false;}
function isFloat(a){ return ((a % 1) == 0 && isNumber(a) ) ? false : true;}
function isObject(a){ return (a && typeof a == 'object') || isFunction(a);}
function isString(a){ return typeof a == 'string'; }
function isUndefined(a){ return typeof a == 'undefined'; } 
function isEmpty(a){ return a == undefined || a == ""; }