I have a some code like this:
var versionPattern = new RegExp("^Firefox/[1]{1}[7-9]{1}|[2-9]{1}[0-9]{1}$");
if (navigator.userAgent.indexOf(versionPattern) > 0) {
alert("Firefox Detected");
return true;
I want to detect versions of Firefox 17 and up but this code doesn't seem to be working correctly. What can I do to improve the RegExp?
Something like:
navigator.userAgent.match(/Firefox\/([1]{1}[7-9]{1}|[2-9]{1}[0-9]{1})/);
Don't use the ^ in your RegExp because Firefox is not the beginning of the String.
And if you want to use the optional 17-19 | 20 - 99, it should be between ( and ).
indexOf is to find the first index of a string inside another string.
The variable you need is var majorVersion
The code example below uses navigator.userAgent to implement browser detection. It also uses navigator.appName and navigator.appVersion as a last resort only, if the userAgent string has an "unexpected" format. In your browser, this code produces the following output:
Browser name = Mozilla Firefox
Full version = 28.0
Major version = 28
navigator.appName = Netscape
navigator.userAgent = Mozilla/5.0 (Windows NT 6.2; WOW64; rv:28.0) Gecko/20100101 Firefox/28.0
And here is the source code that performed the browser detection:
<script>
var nVer = navigator.appVersion;
var nAgt = navigator.userAgent;
var browserName = navigator.appName;
var fullVersion = ''+parseFloat(navigator.appVersion);
var majorVersion = parseInt(navigator.appVersion,10); // this is what you need
var nameOffset,verOffset,ix;
// In Firefox, the true version is after "Firefox"
if ((verOffset=nAgt.indexOf("Firefox"))!=-1) {
browserName = "Firefox";
fullVersion = nAgt.substring(verOffset+8);
}
// In most other browsers, "name/version" is at the end of userAgent
else if ( (nameOffset=nAgt.lastIndexOf(' ')+1) <
(verOffset=nAgt.lastIndexOf('/')) )
{
browserName = nAgt.substring(nameOffset,verOffset);
fullVersion = nAgt.substring(verOffset+1);
if (browserName.toLowerCase()==browserName.toUpperCase()) {
browserName = navigator.appName;
}
}
// trim the fullVersion string at semicolon/space if present
if ((ix=fullVersion.indexOf(";"))!=-1)
fullVersion=fullVersion.substring(0,ix);
if ((ix=fullVersion.indexOf(" "))!=-1)
fullVersion=fullVersion.substring(0,ix);
majorVersion = parseInt(''+fullVersion,10);
if (isNaN(majorVersion)) {
fullVersion = ''+parseFloat(navigator.appVersion);
majorVersion = parseInt(navigator.appVersion,10);
}
document.write(''
+'Browser name = '+browserName+'<br>'
+'Full version = '+fullVersion+'<br>'
+'Major version = '+majorVersion+'<br>'
+'navigator.appName = '+navigator.appName+'<br>'
+'navigator.userAgent = '+navigator.userAgent+'<br>'
)
</script>
You can read the userAgent string and match the version number-
var bs=navigator.userAgent.match(/Firefox\/(\d+)/);
if(bs && parseInt(bs[1])>17) alert('Firefox '+bs[1]+' detected.')
You can test your regular expression with *REGEX*.test('testString');
it returns true / false. I could find strings like "Firefox17" "Firefox22" ... by this regular Expression : /^(Firefox)[1]{1}[7-9]{1}|[2]{1}[0-9]{1}$ so you might try that :
/^(Firefox)[1]{1}[7-9]{1}|[2]{1}[0-9]{1}$.test(navigator.userAgent)
testormatchinstead ofindexOf