■スクリプト
<HTML> <HEAD> <TITLE>prototype</TITLE> </HEAD> <BODY bgColor="white"> <CENTER> <H1>プロパティの追加</H1> </CENTER> <SCRIPT Language="JavaScript"> <!-- Date.prototype.OpenSpace = "By OpenSpace"; theDate = new Date(); alert(theDate.OpenSpace); // --> </SCRIPT> </BODY> </HTML>