本文首先從類型強制與內容規整的角度，提出「消費者契約法定原則」。其次，本文主張在契約成立以前的階段，宜根據當事人之屬性來決定其所負義務之程度，例如以設計、生產、製造、輸入、經銷商品或提供服務為營業之當事人，應負抽象輕過失之先契約義務，而不具營業人屬性之當事人，則僅負具體輕過失之先契約義務。以戴爾電腦標錯價事件為例，網購業者依民法第88 條第1 項但書就其錯誤或不知事情的注意程度，原則上固負抽象輕過失的注意義務，但所謂以其錯誤或不知事情，非由表意人自己之過失者為限，尚且應從「比較過失」的觀點，較量表意人與相對人之各別過失程度的嚴重性、或可歸責程度之高低，來判定表意人在法律評價上是否仍有過失，並據此決定表意人可否撤銷錯誤之意思表示。

The purpose of this article, which is divided into three parts, is to
advance the principle of specifications in Taiwanese consumer contract
and to analyze the recent issue in B2C Internet commerce. Following an
introduction, Part II explores the exact time of formation of sale
contract concluded by Internet, on one hand, and examines the right to
revoke an expression under a mistake, on the other hand. This article
proposes to interpret the Article 88 of Taiwanese Civil Code in the light
of “comparative negligence”. That is to say, when determining whether
a mistaken party could revoke his expression of intent, regard should be
had for the comparison of imputations between two parties. Part III
concludes by offering some perspectives to the future regulation concerning Taiwanese B2C sale contract on Internet.