利用 Javascript 偵測各種IE版本及是否為IE！

// Internet Explorer 6
var IE6 = false /*@cc_on || @_jscript_version < 5.7 @*/;
// exactly Internet Explorer 7
var IE7 = false /*@cc_on || @_jscript_version == 5.7 @*/;
// at least Internet Explorer 7
var gteIE7 = false /*@cc_on || @_jscript_version >= 5.7 @*/;
// any Internet Explorer (thanks to Dean)
var isMSIE = /*@cc_on!@*/false;