JSFiddle - React, Tailwind, and code Playground

HTML

<div id="result"></div>

JavaScript

var myString = "something format_abc something format_def something format_ghi";
var myRegexp = /(?:^|\s)format_(.*?)(?:\s|$)/g;
var match = myRegexp.exec(myString);
//alert(match[1]);  // abc
$("#result").html($("#result").html() + match + "<br>");

while (match != null) {
    match = myRegexp.exec(myString);
    $("#result").html($("#result").html() + match + "<br>");

    // matched text: match[0]
    // match start: match.index
    // capturing group n: match[n]
}