Using replace and regular expressions in JavaScript to implement replaceAll _ javascript skills

In JavaScript, replace is used to achieve the effect of replaceAll. In fact, it is replaced globally with a regular expression. Method:
String. replace (new RegExp (oldString, "gm"), newString ))

Gm stands:
G = global, m = multiLine
In general, this method is used to replace all specified strings.

Another simple method to verify JS:

In the browser address bar, enter
Javascript: alert ("abcabcabc". replace (new RegExp ("a", "gm"), "ad "))

This is easy to use.) I don't know if multiple rows will be very convenient.