The first two arguments must be arrays: 'close' contains the close values, 'volume' contains the volumes.

The 'initialValue' parameter is the initial volume value.

On Balance Volume measures the level of accumulation or distribution by comparing volume to price movements. Volume is added to the indicator if closing price moves up and subtracted if closing price moves down. If the closing price is unchanged no adjustment is made.

A constant increase of the On Balance Volume means that there is an upwards trend. A constant decrease means that there is a downwards trend. If there is a large difference between On Balance Volume and the closing price then there is a market bottom. If there is a small difference between On Balance Volume and the closing price then there is a market top.