{Sample MACD formula}
[target=Default; horzline=0]

n := input("Time periods",9,1);
res := ma(C,12,E) - ma(C,26,E);
signal := ma(res,n,E);

[Name=MACD]
res;
[name=Signal; linestyle=Dash]
signal;

{Signals}
[linestyle=signal; signal=Buy]
cross(res,signal) 
[linestyle=signal; signal=Sell]
cross(signal,res)

BullCharts introduces a powerful, yet easy to use, scripting language called BullScript, which can be used to build custom indicators.

A BullScript can be as simple as CLOSE*VOLUME, or it can incorporate any of the 200 built-in functions to perform sophisticated calculations.

Many traders publish their indicators on the Internet. To facilitate this, BullScript provide attributes, which can describe semantic information about the script, such as description, citation and category. You can also use attributes such as color, line style and target to control how your indicator will be displayed.

Most of the indicators that come with BullCharts are actually written in BullScript, and you can even see and copy the formulas for those indicators.