%% generate tags start %% #software-engineering %% generate tags end %% #software-engineering/javascript In JavaScript, the `replace` and `replaceAll` methods are used to replace parts of a string with new values. The main difference between them is how they deal with the replacement operation: - `replace` replaces only the first occurrence of the specified pattern with the provided replacement. If the pattern appears multiple times in the string, only the first occurrence is replaced. - `replaceAll` replaces all occurrences of the specified pattern with the provided replacement. It replaces every instance of the pattern in the string. Here's an example to illustrate the difference: ```js const string = 'Hello, hello, hello!'; const replaced = string.replace('hello', 'Hi'); const replacedAll = string.replaceAll('hello', 'Hi'); console.log(replaced); // Output: "Hi, hello, hello!" console.log(replacedAll); // Output: "Hi, Hi, Hi!" ``` In the example, `replace` only replaces the first occurrence of "hello" with "Hi", while `replaceAll` replaces all occurrences of "hello" with "Hi" in the string.