/* Javascript functions
isArray
isNull
isEmpty
isObject
isUndefined
isFunction
*/

function isArray(a) { return typeof a == 'object' && a.constructor == Array; }
function isNull(a) { return typeof a == 'object' && !a; }
function isEmpty(o) { var i, v; if (isObject(o)) { for (i in o) { v = o[i]; if (isUndefined(v) && isFunction(v)) { return false; } } } return true; }
function isObject(a) { return (a && typeof a == 'object') || isFunction(a); }
function isUndefined(a) { return typeof a == 'undefined'; }
function isFunction(a) { return typeof a == 'function'; }