function isUndefined(a) {
    return typeof a == 'undefined';
} 
function isObject(a) {
    return (a && typeof a == 'object') || isFunction(a);
}
function isNull(a) {
    return typeof a == 'object' && !a;
}
function isAlfaNumeric(vnos,space) {
if (space==false) {
validRegExp = /^[a-zA-Z0-9]{0,}$/;
}
else {
validRegExp = /^[a-zA-Z0-9\s]{0,}$/;
}
return (vnos.search(validRegExp)!=-1)
}