We present the potential for discovering the standard model Higgs boson produced via the vector-boson fusion mechanism. We considered the decay of Higgs bosons to the W+W- final state, with both W-bosons subsequently decaying leptonically. The main background is tt produced in association with one or more jets. This study is based on a full simulation of the CMS detector. The result is that a signal of 5σ significance can be obtained with an integrated luminosity of 12-72 fb-1 for Higgs boson masses in the range 130<mH<∈200 GeV. In addition, the major background can be measured directly to 7% from the data with an integrated luminosity of 30 fb-1. We also suggest a method to determine the Higgs mass using template transverse mass distributions.