[HTML/Javascript] JS判断IE浏览器各版本

function isLowIEVersion() {

    var browser = navigator.appName
    var b_version = navigator.appVersion
    var version = b_version.split(";");
    var trim_Version = version[1].replace(/[ ]/g, "");

    if (browser == "Microsoft Internet Explorer" && trim_Version == "MSIE6.0") {
        return true;
    } else if (browser == "Microsoft Internet Explorer" && trim_Version == "MSIE7.0") {
        return true;
    } else if (browser == "Microsoft Internet Explorer" && trim_Version == "MSIE8.0") {
        return true;
    }
    
    return false;
}