Javelins are primarily a throwing weapon, but can be used for melee combat as well. In Diablo II there There are no magical throwing weapons, and it's very hard to succeed with a javelin in melee. Crushing Blow is mandatory, usually in the form of Goblin Toes, and Lightning Fury or Plague Javelin are used for the majority of the damage.

In the Expansion this should is still be the way, but with the bigger damage elite javelins, and Magical/Rare/Set javelins, they will be are more viable melee weapons, and of course Crushing Blow is still a helpful addition. Javelins also now have their damage bonus 50/50 Str/Dex, which helps a lot, adding damage from points in Dexterity as well as Strength, and since most javelins require a lot of Dex to equip, that's a natural fit.