Pine Script - EMA Cross Plotting

study(title="MA Cross", overlay=true)
// Moving Average Crosses
// source:  https://www.tradingview.com/i/fgF8j5wH
// original idea: https://www.tradingview.com/u/CosmicDust/
// Thanks: Cosmic Dust
//
// Rewrite for Tradingview "Pine Script" by Kocurekc, April 2014
// https://www.tradingview.com/u/kocurekc/
// Code is provided as public domain, no warranty

len1 = input(title="EMA Period Short", type=integer, defval=12, minval=2)
len2 = input(title="EMA Period Long", type=integer, defval=20, minval=2)
B = input(title="Plot EMA Lines?", type=bool, defval=true)

short = ema(close, len1)
long = ema(close, len2)
plot(B ? short : na, color = red)
plot(B ? long : na, color = green)

clr = short > long ? green : red
plot(cross(short, long) ? short : na, style = cross, color = clr, linewidth = 4)