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

Hi to all.

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;

var mystring = mystring.replace(/test/g, mystring);

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:

var stringToFind = "test";

//first try

mystring = mystring.replace('/' + stringToFind + '/g', mystring);

//second try, not much sense at all

mystring = mystring.replace(/stringToFind/g, mystring);

but they don't work. Any ideas?

From stackoverflow

• 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"
  

  Ropstah : This one helped me!

  KClough : It also helped me!

  Nicky Hajal : Same here, thanks!

• Try:

  var stringToFind = "test";
  mystring = mystring.replace(new RegExp(stringToFind, "g"), mystring);
  

  KooiInc : I suppose the last' mystring' in the replace is not what you meant?

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

  var r = new RegExp(stringToFind, 'g');
  mystring.replace(r, 'some replacement text');
  

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

  https://developer.mozilla.org/en/Core_JavaScript_1.5_Guide/Regular_Expressions

  Example:

  var str = "This is my name";
  var replace = "i";
  var re = new RegExp(replace, 'g')    
  
  str = str.replace(re, 'p');
  alert(str);
  

• For regex, new RegExp(stringtofind, 'g');. 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:

  mystring= mystring.split(stringtofind).join(replacementstring);
  

  Thomas : +1 always good to see people thinking beyond the literal answer to the question.

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

  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"
  

  It will also take regular expressions. To me this is one of the more elegant ways to solve it. prototypejs gsub documentation

• 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);
  

  silmiar post

• Thanks to all, i've got the point! Before i didn't know how to manage regex in javascript..

  Yes i use the prototype framework, and before posting this question i've searched into the prototype String documentation, but found nothing, i'm so dumb :|