JS GB2312转UTF8 支持中英文混合

JSGB2312TOUTF8UTF8TOGB2312编码转换/**GB2312转UTF8*例：*varxx=newGB2312UTF8();*varUtf8=xx.Gb2312ToUtf8("你aaa好aaaaa");*varGb2312=xx.Utf8ToGb2312(Utf8);*alert(Gb2312);*/