How to replace in Javascript?

Question

I can't figure out why this code isn't working.

I want to replace a placeholder with an actual value. Sample code as below:

var str = "ID: :ID:";
str.replace(":ID:", 0);
console.log(str);

Output:

ID: :ID:

This is my JSFiddle

• Raul Rene: You have to assign the value back to str
• T.J. Crowder: possible duplicate of Replacing all occurrences of a string in javascript?

Answer 1

The replace() method searches a string for a specified value, or a regular expression, and returns a new string where the specified values are replaced.

var str = "ID: :ID:";
str = str.replace(":ID:", 0);
console.log(str);

replace

P.s. replace only replaces the first occurrence.
Use replace all if you want to replace all occurrences:
How to replace all occurrences of a string in JavaScript?

• Fabio Filippi: Replace all: stackoverflow.com/questions/1144783/…
• T.J. Crowder: If you pass find raw into the RegExp constructor, the various regex special characters will cause trouble. For instance, if find is "Mr. Smith" you'll replace "Mrs Smith" as well.
• Amir Popovich: @T.J.Crowder - Your'e right about that, I've searched for a fix and edited my post.

Answer 2

Your just replacing the string, but not storing it back. So, it is giving previous string rather than new one.

var str = "ID: :ID:";
str = str.replace(":ID:", 0);
console.log(str);

JS Fiddle: http://jsfiddle.net/B9n79/2/

• T.J. Crowder: Note that this will only replace the first occurrence of :ID:.
• suneetha: Yes. we can use regular expressions to replace all occurrences

Answer 3

Try this:

var str = "ID: :ID:";
str = str.replace(/:ID:/gi, "0");
console.log(str);