blocks|key|1308888|text|类似于：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1308889|navigator.userAgent.match(/Firefox\/([1]{1}[7-9]{1}%7C[2-9]{1}[0-9]{1})/);|code-block|syntax|javascript|1308890|不要在%5E中使用RegExp，因为Firefox不是字符串的开头。如果您想使用可选的17-19+\+20+-+99，它应该在(和)之间。|offset|length|style|CODE|BOLD|1308891|indexOf是在另一个字符串中查找字符串的第一个索引。|1308892|entityMap|0|LINK|mutability|MUTABLE|url|https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/String/indexOf^0|0|0|3|1|1P|1|1R|1|G|7|0|0|7|0|0^^$0|@$1|2|3|4|5|6|7|X|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|Y|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Z|8|@$I|10|J|11|K|L]|$I|12|J|13|K|L]|$I|14|J|15|K|L]|$I|16|J|17|K|M]]|9|@]|A|$]]|$1|N|3|O|5|6|7|18|8|@]|9|@$I|19|J|1A|1|1B]]|A|$]]|$1|P|3|-4|5|6|7|1C|8|@]|9|@]|A|$]]]|Q|$R|$5|S|T|U|A|$V|W]]]]

Something like:

<pre><code>navigator.userAgent.match(/Firefox\/([1]{1}[7-9]{1}|[2-9]{1}[0-9]{1})/);
</code></pre>

Don't use the <code>^</code> 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 <code>(</code> and <code>)</code>.

<a href="https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/String/indexOf" rel="nofollow">indexOf</a> is to find the first index of a string inside another string.

blocks|key|2028219|text|您可以读取userAgent字符串和匹配版本号-|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|2028220|var+bs=navigator.userAgent.match(/Firefox\/(\d%2B)/);
if(bs+&&+parseInt(bs[1])>17)+alert('Firefox+'%2Bbs[1]%2B'+detected.')|code-block|syntax|javascript|2028221|entityMap^0|I|2|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

You can read the userAgent string and match the version number-

<pre><code>var bs=navigator.userAgent.match(/Firefox\/(\d+)/);
if(bs &amp;&amp; parseInt(bs[1])&gt;17) alert('Firefox '+bs[1]+' detected.')
</code></pre>

blocks|key|2028227|text|您可以使用*REGEX*.test('testString');测试正则表达式，它返回true+/+false。我可以找到像"Firefox17“"Firefox22”这样的字符串..。通过这个正则表达式:/%5E(火狐)1{1}7-9{1}\2{1}{1}0-9{1}$，所以您可以尝试：/%5E(Firefox)[1]{1}[7-9]{1}%7C[2]{1}[0-9]{1}$.test(navigator.userAgent)|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|2028228|entityMap^0|5|R|3Z|1V|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]|$9|K|A|L|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|M|8|@]|D|@]|E|$]]]|G|$]]

You can test your regular expression with <code>*REGEX*.test('testString');</code>
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 : 
<code>/^(Firefox)[1]{1}[7-9]{1}|[2]{1}[0-9]{1}$.test(navigator.userAgent)</code>

blocks|key|1308941|text|您需要的变量是var+majorVersion。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1308942|下面的代码示例使用navigator.userAgent实现浏览器检测。它还使用navigator.appName和navigator.appVersion作为最后手段，如果userAgent字符串具有“意外”格式的话。在浏览器中，此代码生成以下输出：|blockquote|1308943|浏览器名称=+Mozilla+Firefox|1308944|全文=+28.0|1308945|主要版本=+28|1308946|navigator.appName+=网景|1308947|navigator.userAgent+=+Mozilla/5.0+(WindowsNT6.2；WOW64；rv:28.0)|1308948|下面是执行浏览器检测的源代码：|1308949|演示|1308950|+++<script>++
++++var+nVer+=+navigator.appVersion;
++++var+nAgt+=+navigator.userAgent;
++++var+browserName++=+navigator.appName;
++++var+fullVersion++=+''%2BparseFloat(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%2B8);
}
//+In+most+other+browsers,+"name/version"+is+at+the+end+of+userAgent+
else+if+(+(nameOffset=nAgt.lastIndexOf('+')%2B1)+<+
++++++++++(verOffset=nAgt.lastIndexOf('/'))+)+
{
+browserName+=+nAgt.substring(nameOffset,verOffset);
+fullVersion+=+nAgt.substring(verOffset%2B1);
+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(''%2BfullVersion,10);
if+(isNaN(majorVersion))+{
+fullVersion++=+''%2BparseFloat(navigator.appVersion);+
+majorVersion+=+parseInt(navigator.appVersion,10);
}

document.write(''
+%2B'Browser+name++=+'%2BbrowserName%2B' '
+%2B'Full+version++=+'%2BfullVersion%2B' '
+%2B'Major+version+=+'%2BmajorVersion%2B' '
+%2B'navigator.appName+=+'%2Bnavigator.appName%2B' '
+%2B'navigator.userAgent+=+'%2Bnavigator.userAgent%2B' '
)
</script>|code-block|syntax|javascript|1308951|SRC|1308952|entityMap|0|LINK|mutability|MUTABLE|url|http://jsfiddle.net/tuga/WrwL5/|1|http://www.javascripter.net/faq/browsern.htm^0|7|G|0|0|0|0|0|0|0|0|0|2|0|0|0|0|3|1|0^^$0|@$1|2|3|4|5|6|7|1D|8|@$9|1E|A|1F|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|1G|8|@]|D|@]|E|$]]|$1|I|3|J|5|6|7|1H|8|@]|D|@]|E|$]]|$1|K|3|L|5|6|7|1I|8|@]|D|@]|E|$]]|$1|M|3|N|5|6|7|1J|8|@]|D|@]|E|$]]|$1|O|3|P|5|6|7|1K|8|@]|D|@]|E|$]]|$1|Q|3|R|5|6|7|1L|8|@]|D|@]|E|$]]|$1|S|3|T|5|6|7|1M|8|@]|D|@]|E|$]]|$1|U|3|V|5|6|7|1N|8|@]|D|@$9|1O|A|1P|1|1Q]]|E|$]]|$1|W|3|X|5|Y|7|1R|8|@]|D|@]|E|$Z|10]]|$1|11|3|12|5|6|7|1S|8|@]|D|@$9|1T|A|1U|1|1V]]|E|$]]|$1|13|3|-4|5|6|7|1W|8|@]|D|@]|E|$]]]|14|$15|$5|16|17|18|E|$19|1A]]|1B|$5|16|17|18|E|$19|1C]]]]

The variable you need is <code>var majorVersion</code>

<blockquote>
 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:
</blockquote>

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: 

<a href="http://jsfiddle.net/tuga/WrwL5/" rel="nofollow">DEMO</a>

<pre><code> &lt;script&gt; 
 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) &lt; 
 (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+'&lt;br&gt;'
 +'Full version = '+fullVersion+'&lt;br&gt;'
 +'Major version = '+majorVersion+'&lt;br&gt;'
 +'navigator.appName = '+navigator.appName+'&lt;br&gt;'
 +'navigator.userAgent = '+navigator.userAgent+'&lt;br&gt;'
)
&lt;/script&gt;
</code></pre>

<a href="http://www.javascripter.net/faq/browsern.htm" rel="nofollow">SRC</a>

I have a some code like this:

<pre><code>var versionPattern = new RegExp("^Firefox/[1]{1}[7-9]{1}|[2-9]{1}[0-9]{1}$");

if (navigator.userAgent.indexOf(versionPattern) &gt; 0) {
 alert("Firefox Detected");
 return true;
</code></pre>

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?

Detecting specific browser with JavaScript RegExp

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我有这样的代码：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;我想检测Fir

问用JavaScript RegExp检测特定浏览器
EN

回答 4

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