脚本获取网页中选中文字
var word = document.selection.createRange().text;
获取选中文字所在的句子
var range = document.selection.createRange();
range.expand("sentence");
var sentence = range.text;

给IE右键菜单添加菜单项参见http://www.codeproject.com/jscript/CopyasHTML.asp
http://www.cnblogs.com/zuolun/archive/2006/12/04/580998.html