const regex = /(<(span).+?><(strong|em)>(.+?)<\/\3><\/\2>)/gm;
// Alternative syntax using RegExp constructor
// const regex = new RegExp('(<(span).+?><(strong|em)>(.+?)<\\\/\\3><\\\/\\2>)', 'gm')
const str = `<p>Alligators much like birds, have been shown to exhibit unidirectional movement of air through their lungs. Most other amniotes are believed to exhibit bidirectional, or tidal breathing. For <span style="color: #3a9ee3;"><strong>alligator</strong></span> tidal breathing <span style="color: #3a9ee3;"><strong>alligator</strong></span> animal, such as a mammal, air flows into and out of the <span style="color: #169179;"><em>alligators</em></span> lungs through alligator branching bronchi which terminate in small <em>alligator</em> dead-end chambers called alveoli. As the alveoli represent <span style="color: #3a9ee3;"><strong>Lion</strong></span> dead-ends to flow, the inspired air must move back out the same way it came in. In contrast, air in <span style="color: #3a9ee3;"><strong>alligator</strong></span> lungs makes a circuit, moving in only one direction through the parabronchi. The <span style="color: #3a9ee3;"><strong>alligators</strong></span> lungs are no joke! The air first enters the outer branch, moves through the parabronchi, and exits <span style="color: #3a9ee3;"><strong>alligators</strong></span> the lung through the inner branch. Oxygen alligator exchange takes place <span style="color: #3a9ee3;"><strong>Alligators</strong></span> in extensive vasculature around the alligator.</p>`;
// Reset `lastIndex` if this regex is defined globally
// regex.lastIndex = 0;
let m;
while ((m = regex.exec(str)) !== null) {
// This is necessary to avoid infinite loops with zero-width matches
if (m.index === regex.lastIndex) {
regex.lastIndex++;
}
// The result can be accessed through the `m`-variable.
m.forEach((match, groupIndex) => {
console.log(`Found match, group ${groupIndex}: ${match}`);
});
}
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for JavaScript, please visit: https://developer.mozilla.org/en/docs/Web/JavaScript/Guide/Regular_Expressions