Simple snippet to do regular expression search in a Chrome Snippet.

chrome-snippet-regex-search.js

reText = prompt('RegExp?');

backgroundColor = 'rgba(255,255,80,0.5)';
outline = `3px solid ${backgroundColor}`;

matchClass = 're-match';


{  // clear old matches

const nodes = [];
Array.prototype.forEach.call(document.getElementsByClassName(matchClass), node => {nodes.push(node)});
nodes.forEach(node => { node.replaceWith(node.innerText); });

};


[plain, ...complex] = reText.split('/');
complex = complex || [];
flags = complex.pop() || 'g';
re = new RegExp(complex.join('/') || plain, flags);
console.log(`Searching for /${re.source}/${flags}`);
document.body.normalize();
Array.prototype
    .filter.call(document.body.querySelectorAll('*'), node => re.test(node.innerText))
    .reverse()
    .filter((node, i, arr) => !arr.slice(0, i).some(child => node.contains(child)))
    .reverse()
    .map(node => {
      node.textContent.replace(re, (nMatch, nIndex, nFullString) => {
        let currIndex = 0;
        const nodes = [];
        node.normalize();
        node.childNodes.forEach(node => {nodes.push(node)}); // copy to prevent live changes
        nodes.find(c => {
          let p = node;
          if (c.nodeName != '#text') {
            p = c;
            c = c.firstChild;
          }
          let nextIndex = currIndex + (c ? c.textContent.length : 0);
          if (nextIndex > nIndex) {
            const matchIndexStart = nIndex - currIndex;
            const matchLen = Math.min(c.textContent.length - matchIndexStart, nMatch.length);
            const matchPart = nMatch.substr(0, matchLen);

            const newNode = c.splitText(matchIndexStart);
            newNode.textContent = newNode.textContent.substr(matchLen);
            nMatch = nMatch.substr(matchLen);
            nIndex += matchLen;

            const span = document.createElement('span');
            span.innerText = matchPart;
            span.style.backgroundColor = backgroundColor;
            span.style.outline = outline;
            span.classList.add(matchClass)
            p.insertBefore(span, newNode);
          }
          currIndex = nextIndex;
          return nextIndex >= nIndex + nMatch.length;
        });
      });
      return node;
    });