一个非常实用的javascript读写Cookie函数

function GetCookieVal(offset)//获得Cookie解码后的值{var endstr = document.cookie.indexOf (";", offset);if (endstr == -1)endstr = document.cookie.length;return unescape(document.cookie.substring(offset, endstr));}function SetCookie(name, value)//设定Cookie值{var expdate = new Date();var argv = SetCookie.arguments;var argc = SetCookie.arguments.length;var expires = (argc > 2) ? argv[2] : null;var path = (argc > 3) ? argv[3] : null;var domain = (argc > 4) ? argv[4] : null;var secure = (argc > 5) ? argv[5] : false;if(expires!=null) expdate.setTime(expdate.getTime() + ( expires * 1000 ));document.cookie = name + "=" + escape (value) +((expires == null) ? "" : ("; expires="+ expdate.toGMTString()))+((path == null) ? "" : ("; path=" + path)) +((domain == null) ? "" : ("; domain=" + domain))+((secure == true) ? "; secure" : "");}function DelCookie(name)//删除Cookie{var exp = new Date();exp.setTime (exp.getTime() - 1);var cval = GetCookie (name);document.cookie = name + "=" + cval + "; expires="+ exp.toGMTString();}function GetCookie(name)//获得Cookie的原始值{var arg = name + "=";var alen = arg.length;var clen = document.cookie.length;var i = 0;while (i < clen){var j = i + alen;if (document.cookie.substring(i, j) == arg)return GetCookieVal (j);i = document.cookie.indexOf(" ", i) + 1;if (i == 0) break;}return null;}