@scottb You can try:
const value = $w("#searchText").value;
const p = src_str.split(">").filter(e => e).map(e => ({particle: e}));
let t = p.filter(e => !e.particle.trim().startsWith("<")).map(e => {e.particle = e.particle.split("<"); return e;}).map(e => {e.particle[0] = e.particle[0].replace(value, `<span style="color:red;">${value}</span>`); return e;});
t.forEach(e => e.particle = e.particle.join("<"));
$item("#text85").html = p.reduce((a,c) => a + c.particle + ">", "");