JSFiddle - React, Tailwind, and code Playground

HTML

<div>foo bar
    <h1>Hello {{name}}!</h1>
</div>

JavaScript

function getPlaceholders(elem) {
    var html = elem.firstChild.data;
    if(html && (matches = html.match(/{{(.+)}}/g))){
        console.log(elem, "I am here");
    }
    
    
    var elements = elem.children;
    if (elements.length) {
        for(var i = 0; i < elements.length; i++) {
            getPlaceholders(elements[i]);
        }
    }
}

getPlaceholders(document.body);