Show a message if the browser is not internet explorer 9 or greater

Question

I would like to show my users a bar that looks like this, if:

1. Browser is not IE; or
2. Browser is IE but is version 8 or earlier

Answer 1

EDIT: This directly answers the OP.

I have updated Dany's answer with two updates tested in (IE 6,7,8,9,10,11), Chrome, and Edge. Primarily because the updates are very hard to read in the comments.

• Pure javascript - No jQuery required
• IE10 reports IE 10 vs IE 1
• This now reports Edge
• No specific HTML elements required to pre-exist (other than a body)
• Tested in IE6, IE7, IE8, IE9, IE11, Chrome v62, and Edge
• TODO: get it working properly in OSX Sierra, and iPhone

The test for edge must be first as it claims to be everything. :/

All this being said Browser detection "is what it is" and we can hope that the need for it will go away soon.

browser = {};
if (/(Edge\/[0-9]{2})/i.test(navigator.userAgent)) {
    browser.agent = navigator.userAgent.match(/(Edge\/[0-9]{2})/i)[0].split("/")[0];
    browser.version = parseInt(navigator.userAgent.match(/(Edge\/[0-9]{2})/i)[0].split("/")[1]);
} else if (/(chrome\/[0-9]{2})/i.test(navigator.userAgent)) {
    browser.agent = navigator.userAgent.match(/(chrome\/[0-9]{2})/i)[0].split("/")[0];
    browser.version = parseInt(navigator.userAgent.match(/(chrome\/[0-9]{2})/i)[0].split("/")[1]);
} else if (/(firefox\/[0-9]{2})/i.test(navigator.userAgent)) {
    browser.agent = navigator.userAgent.match(/(firefox\/[0-9]{2})/i)[0].split("/")[0];
    browser.version = parseInt(navigator.userAgent.match(/(firefox\/[0-9]{2})/i)[0].split("/")[1]);
} else if (/(MSIE\ [0-9]{1})/i.test(navigator.userAgent)) {
    browser.agent = navigator.userAgent.match(/(MSIE\ [0-9]{1})/i)[0].split(" ")[0];
    browser.version = parseInt(navigator.userAgent.match(/(MSIE\ [0-9]+)/i)[0].split(" ")[1]);
} else if (/(Opera\/[0-9]{1})/i.test(navigator.userAgent)) {
    browser.agent = navigator.userAgent.match(/(Opera\/[0-9]{1})/i)[0].split("/")[0];
    browser.version = parseInt(navigator.userAgent.match(/(Opera\/[0-9]{1})/i)[0].split("/")[1]);
} else if (/(Trident\/[7]{1})/i.test(navigator.userAgent)) {
    browser.agent = "MSIE";
    browser.version = 11;
} else {
    browser.agent = false;
    browser.version = false;
}

if (/(Windows\ NT\ [0-9]{1}\.[0-9]{1})/.test(navigator.userAgent)) {
    browser.os = "Windows";

    switch (parseFloat(navigator.userAgent.match(/(Windows\ NT\ [0-9]{1}\.[0-9]{1})/)[0].split(" ")[2])) {
        case 6.0:
            browser.osversion = "Vista";
            break;
        case 6.1:
            browser.osversion = "7";
            break;
        case 6.2:
            browser.osversion = "8";
            break;
        default:
            browser.osversion = false;
    }
} else if (/(OS\ X\ [0-9]{2}\.[0-9]{1})/.test(navigator.userAgent)) {
    browser.os = "OS X";
    browser.osversion = navigator.userAgent.match(/(OS\ X\ [0-9]{2}\.[0-9]{1})/)[0].split(" ")[2];
} else if (/(Linux)/.test(navigator.userAgent)) {
    browser.os = "Linux";
    browser.osversion = false;
}

if (browser.agent === "MSIE" && browser.version <= 9) {
    var newDiv = document.createElement("div");
    newDiv.innerHTML = "IE9 is not supported. You are using an UNSUPPORTED version of Internet Explorer.";
    newDiv.setAttribute("style", "background-color:yellow;padding:18px;");
    document.body.insertBefore(newDiv, document.body.firstChild);
} else { //TODO: Remove for Prod only added to show some flexibility and testing 
    var newDiv = document.createElement("div");
    newDiv.innerHTML = "" + browser.agent + " is so supported. You are using version: " + browser.version + ".";
    newDiv.setAttribute("style", "background-color:cyan;padding:12px;");
    document.body.insertBefore(newDiv, document.body.firstChild);
}