This paper is concerned with the use of numeric ActiveX components for mathematical modelling on HTML Web pages. These Web pages may either be stored on a computer’s local disk or reside on a remote machine to which there is access via Intranet or Internet connectivity. The Web pages considered here contain HTML and script which are interpreted by means of a Web browser. Three demonstration applications, which make use of numerical optimization, are considered here. They are taken from the fields of mathematical finance and physics. 1 Keywords