The following objects are built into the Javascript runtime:

Math

fabs(x);
acos(x);
asin(x);
atan(x);
ceil(x);
cos(x);
exp(x);
floor(x);
log(x);
round(x);
sin(x);
sqrt(x);
tan(x);

Date

now();
getFullYear();
getUTCFullYear();
getMonth();
getUTCMonth();
getDate();
getUTCDate();
getDay();
getUTCDay();
getHours();
getUTCHours();
getMinutes();
getUTCMinutes();
getSeconds();
getUTCSeconds();
getMilliseconds();
getUTCMilliseconds();
getYear();

Example

print(Math.floor(1.5)); // Expected result is 1
print(Date.now()); // Returns current moment as number of milliseconds since January 1, 1970, 00:00:00 UTC.
                   // This is how the built-in function delay() is implemented.