■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"> <!-- Number.prototype.OpenSpace = 1969; theNum = new Number(); document.write(theNum.OpenSpace); // --> </SCRIPT> </BODY> </HTML>