blocks|key|1412648|text|var+mystring+=+"hello+world+test+world";
var+find+=+"world";
var+regex+=+new+RegExp(find,+"g");
alert(mystring.replace(regex,+"yay"));+//+alerts+"hello+yay+test+yay"|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1412649|以防您需要将其放入函数中|unstyled|1412650|++replaceGlobally(original,+searchTxt,+replaceTxt)+{
++++const+regex+=+new+RegExp(searchTxt,+'g');
++++return+original.replace(regex,+replaceTxt)+;
++}|1412651|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|L|8|@]|9|@]|A|$]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$B|C]]|$1|I|3|-4|5|F|7|N|8|@]|9|@]|A|$]]]|J|$]]

<pre><code>var mystring = "hello world test world";
var find = "world";
var regex = new RegExp(find, "g");
alert(mystring.replace(regex, "yay")); // alerts "hello yay test yay"
</code></pre>

In case you need this into a function

<pre><code> replaceGlobally(original, searchTxt, replaceTxt) {
 const regex = new RegExp(searchTxt, 'g');
 return original.replace(regex, replaceTxt) ;
 }
</code></pre>

blocks|key|1412659|text|尝试：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1412660|var+stringToFind+=+"test";
mystring+=+mystring.replace(new+RegExp(stringToFind,+"g"),+mystring);|code-block|syntax|javascript|1412661|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Try:

<pre><code>var stringToFind = "test";
mystring = mystring.replace(new RegExp(stringToFind, "g"), mystring);
</code></pre>

blocks|key|1412706|text|这是一个正则表达式，不是字符串。使用RegExp对象的构造函数动态创建正则表达式。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1412707|var+r+=+new+RegExp(stringToFind,+'g');
mystring.replace(r,+'some+replacement+text');|code-block|syntax|javascript|1412708|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Thats a regular expression, not a string. Use the constructor for a RegExp object to dynamically create a regex.

<pre><code>var r = new RegExp(stringToFind, 'g');
mystring.replace(r, 'some replacement text');
</code></pre>

blocks|key|1627384|text|如果要插入变量，则需要使用RegExp对象|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1627385|https://developer.mozilla.org/en/Core_JavaScript_1.5_Guide/Regular_Expressions|offset|length|1627386|示例：|1627387|var+str+=+"This+is+my+name";
var+replace+=+"i";
var+re+=+new+RegExp(replace,+'g')++++

str+=+str.replace(re,+'p');
alert(str);|code-block|syntax|javascript|1627388|entityMap|0|LINK|mutability|MUTABLE|url^0|0|0|26|0|0|0|0^^$0|@$1|2|3|4|5|6|7|T|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|U|8|@]|9|@$D|V|E|W|1|X]]|A|$]]|$1|F|3|G|5|6|7|Y|8|@]|9|@]|A|$]]|$1|H|3|I|5|J|7|Z|8|@]|9|@]|A|$K|L]]|$1|M|3|-4|5|6|7|10|8|@]|9|@]|A|$]]]|N|$O|$5|P|Q|R|A|$S|C]]]]

If you want variables interpolated, you need to use the RegExp object

<a href="https://developer.mozilla.org/en/Core_JavaScript_1.5_Guide/Regular_Expressions" rel="nofollow noreferrer">https://developer.mozilla.org/en/Core_JavaScript_1.5_Guide/Regular_Expressions</a>

Example:

<pre><code>var str = "This is my name";
var replace = "i";
var re = new RegExp(replace, 'g') 

str = str.replace(re, 'p');
alert(str);
</code></pre>

blocks|key|1412798|text|对于正则表达式，new+RegExp(stringtofind,+'g');。但。如果‘find’包含正则表达式中的特殊字符，则它们将具有其正则表达式的含义。因此，如果您尝试替换“.”在带有'x‘的'abc.def’中，你会得到‘xxxxxxx’ - 哇。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1412799|如果你想要的只是一个简单的字符串替换，就不需要正则表达式了！下面是简单的字符串替换习惯用法：|1412800|mystring=+mystring.split(stringtofind).join(replacementstring);|code-block|syntax|javascript|1412801|entityMap^0|8|U|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|R|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|S|8|@]|D|@]|E|$K|L]]|$1|M|3|-4|5|6|7|T|8|@]|D|@]|E|$]]]|N|$]]

For regex, <code>new RegExp(stringtofind, 'g');</code>. BUT. If ‘find’ contains characters that are special in regex, they will have their regexy meaning. So if you tried to replace the '.' in 'abc.def' with 'x', you'd get 'xxxxxxx' — whoops.

If all you want is a simple string replacement, there is no need for regular expressions! Here is the plain string replace idiom:

<pre><code>mystring= mystring.split(stringtofind).join(replacementstring);
</code></pre>

blocks|key|1627551|text|你会用prototype.js吗？如果是这样的话，你可以使用String.gsub，比如|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1627552|var+myStr+=+"a+day+in+a+life+of+a+thing";
+var+replace+=+"a";
+var+resultString+=+myStr.gsub(replace,+"g");
+//+resultString+will+be+"g+day+in+g+life+of+g+thing"|code-block|syntax|javascript|1627553|它还将采用正则表达式。对我来说，这是解决这个问题的更优雅的方法之一。prototypejs+gsub+documentation|offset|length|1627554|entityMap|0|LINK|mutability|MUTABLE|url|http://www.prototypejs.org/api/string/gsub^0|0|0|Y|U|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|U|8|@]|9|@$I|V|J|W|1|X]]|A|$]]|$1|K|3|-4|5|6|7|Y|8|@]|9|@]|A|$]]]|L|$M|$5|N|O|P|A|$Q|R]]]]

Can you use prototype.js? If so you could use String.gsub, like 

<pre><code>var myStr = "a day in a life of a thing";
 var replace = "a";
 var resultString = myStr.gsub(replace, "g");
 // resultString will be "g day in g life of g thing"
</code></pre>

It will also take regular expressions. To me this is one of the more elegant ways to solve it. <a href="http://www.prototypejs.org/api/string/gsub" rel="nofollow noreferrer">prototypejs gsub documentation</a>

blocks|key|1412928|text|String.prototype.replaceAll+=+function+(replaceThis,+withThis)+{
+++var+re+=+new+RegExp(RegExp.quote(replaceThis),"g");+
+++return+this.replace(re,+withThis);
};


RegExp.quote+=+function(str)+{
+++++return+str.replace(/([.?*%2B%5E$[\]\\(){}-])/g,+"\\$1");
};

var+aa+=+"qwerr.erer".replaceAll(".","A");
alert(aa);|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1412929|silmiar+post|unstyled|offset|length|1412930|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/questions/494035/how-do-you-pass-a-variable-to-a-regular-expression-javascript/500471#500471^0|0|0|C|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|R|8|@]|9|@$G|S|H|T|1|U]]|A|$]]|$1|I|3|-4|5|F|7|V|8|@]|9|@]|A|$]]]|J|$K|$5|L|M|N|A|$O|P]]]]

<pre><code>String.prototype.replaceAll = function (replaceThis, withThis) {
 var re = new RegExp(RegExp.quote(replaceThis),"g"); 
 return this.replace(re, withThis);
};


RegExp.quote = function(str) {
 return str.replace(/([.?*+^$[\]\\(){}-])/g, "\\$1");
};

var aa = "qwerr.erer".replaceAll(".","A");
alert(aa);
</code></pre>

<a href="https://stackoverflow.com/questions/494035/how-do-you-pass-a-variable-to-a-regular-expression-javascript/500471#500471">silmiar post</a>

blocks|key|1627599|text|正则表达式比字符串搜索慢得多。因此，使用转义搜索字符串创建正则表达式不是最佳方法。即使对字符串进行循环也会更快，但我建议使用内置的预编译方法。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1627600|这是一种快速整洁的全局字符串替换方法：|1627601|sMyString.split(sSearch).join(sReplace);|code-block|syntax|javascript|1627602|就是这样。|1627603|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|N|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|O|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|P|8|@]|9|@]|A|$]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

Regular expressions are much slower then string search. So, creating regex with escaped search string is not an optimal way. Even looping though the string would be faster, but I suggest using built-in pre-compiled methods.

Here is a fast and clean way of doing fast global string replace:

<pre><code>sMyString.split(sSearch).join(sReplace);
</code></pre>

And that's it.

blocks|key|1412998|text|您可以使用以下解决方案对变量在'/‘和’/g‘内的字符串执行全局替换：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1412999|myString.replace(new+RegExp(strFind,+'g'),+strReplace);|code-block|syntax|javascript|1413000|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

You can use the following solution to perform a global replace on a string with a variable inside '/' and '/g':

<pre><code>myString.replace(new RegExp(strFind, 'g'), strReplace);
</code></pre>

I want to perform a global replace of string using String.replace in Javascript.
In the documentation I read that I can do this with /g, i.e. for example;
<pre><code>var mystring = mystring.replace(/test/g, mystring);
</code></pre>
and this will replace all occurrences inside mystring. No quotes for the expression.
But if I have a variable to find, how can I do this without quotes?
I've tried something like this:
<pre><code>var stringToFind = &quot;test&quot;;
</code></pre>
//first try
<pre><code>mystring = mystring.replace('/' + stringToFind + '/g', mystring);
</code></pre>
//second try, not much sense at all
<pre><code>mystring = mystring.replace(/stringToFind/g, mystring);
</code></pre>
but they don't work. Any ideas?

In Javascript, how can I perform a global replace on string with a variable inside '/' and '/g'?

我想在Javascript中使用String.replace执行字符串的全局替换。在我读到的文档中，我可以用/g做到这一点，例如；var mystring = mystring.replace(/test/g, mystring);这将替换mystring中的所有匹配项。表达式没有引号。但是如果我有一个变量需要查找，没...

问在Javascript中，如何使用'/‘和'/g’中的变量对字符串执行全局替换？
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问在Javascript中，如何使用'/‘和'/g’中的变量对字符串执行全局替换？
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