From Overview of Advanced JavaScript -- Web Scripting Language CPS616 Technologies of the Information Age -- Spring Semester 98. byTom Scavo,Geoffrey C. Fox
with ( someObject ) { statements }
someObject is the default object used for any unqualified object references: with ( Math ) { area = PI*r*r; // Math property PI x = r*cos(theta); // Math method cos y = r*sin(theta); // Math method sin }