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Asked: 2026-06-11T01:15:49+00:00

I do not see where my error is, If there is any <!DOCTYPE html>

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I do not see where my error is, If there is any

<!DOCTYPE html> <html> <head>
        <script type="text/javascript">
            //http://stackoverflow.com/questions/10251149/using-javascript-to-detect-google-chrome-to-switch-css
            //provera brosera
            function check_chrome_ua() {
                var ua = navigator.userAgent.toLowerCase();
                var is_chrome = /chrome/.test(ua);
                alert("func check_chrome_ua() " + is_chrome);
                return is_chrome;
            }
            //promena nadpisa
            function check() {
                //alert("check1");

                var check = check_chrome_ua();
                alert("var check " + check + "; func check_chrome_ua() " + check_chrome_ua());

                if (check == "false") {
                    alert("change text");
                    document.getElementById("opomena").style.color = "red";
                    document.getElementById("opomena").innerHTML = 'Warning you are not using Google Chrome';
                }
            }
        </script>
        </head>
        <body onmousemove="check()">
    <div id="opomena">Thank you for using Google Chrome.</div>

</body>
 </html>

Popups on Google Chrome popup says true, on Firefox says false
popup “change text” does not display in Firefox tho var check is false.

Thank you in advance for advice

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1 Answer

  1. Editorial Team

    Change

    if (check == "false") {

    to

    if (!check) {

    or

    if (check == false) {

    if you really want to check for the boolean value, false.

    The regexp, test method which you call at /chrome/.test(ua) returns a boolean, but check == "false" is comparing that boolean to a string. The two are not equal.

    In JavaScript, == is permissive when it comes to comparing strings to objects, but not as permissive as Perl’s eq operator.

    • 0 == false
    • false == false
    • "false" == [false]
    • false != "false"
    • 0 != "false"

    It’s a good habit to try and use !== and === which are well-defined operators to compare primitive values.

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