[R] How to color certain area under curve

[guox at ucalgary.ca]

For a given random variable rv, for instance, rv = rnorm(1000),
I plot its density curve and calculate some quantiles:
plot(density(rv))
P10P50P90 = = quantile(rv,probs = c(10,50,90)/100)
I would like to color the area between P10 and P90 and under the curve
and mark the P50 on the curve.

> rv = rnorm(1000)
> plot(density(rv))
> P10P50P90 = = quantile(rv,probs = c(10,50,90)/100)

Could you please teach me how to do these using R?
Thanks,
-james