input <input name>=<float_number_used_by_default>;
Defines a float input. Note that in order to define this input you need to use a fullstop as a delimiter in its default value.
input percentShift = 10.0;
plot UpperBand = close * (1 + percentShift / 100);
plot LowerBand = close * (1 - percentShift / 100);
Draws the envelope based on the closing price. The percent shift value can be adjusted using the correspondent input, which is set to 10.0 by default.