The CG-plus-live action Charlotte’s Web (Paramount) and The Pursuit of Happyness (Columbia), the Will Smith feel-good drama, are both going to do $20 million-plus this weekend. Tracking has Web running 85, 31, 9 — very good for an animated film — and Pursuit is at 81, 51 and 18. 20th Century Fox’s Eragon will be close behind them — 61, 34 and 13. Rocky Balboa (12.20) — 84,29, 6; The Good Shepherd (12.22) — 62, 34, 4; Fox’s A Night at the Museum (12.22) — 73, 41, and 7 (still looking big); We Are Marshall (12.22) — 57, 31, 4; Black Christmas (12.25) — 37, 25, something. Dreamgirls (12.25) — 70, 30 , 5.