How to get element by innerText

Simply pass your substring into the following line:

Outer HTML

document.documentElement.outerHTML.includes('substring')

Inner HTML

document.documentElement.innerHTML.includes('substring')

You can use these to search through the entire document and retrieve the tags that contain your search term:

function get_elements_by_inner(word) {
    res = []
    elems = [...document.getElementsByTagName('a')];
    elems.forEach((elem) => { 
        if(elem.outerHTML.includes(word)) {
            res.push(elem)
        }
    })
    return(res)
}

Usage:

How many times is the user "T3rm1" mentioned on this page?

get_elements_by_inner("T3rm1").length

1

How many times is jQuery mentioned?

get_elements_by_inner("jQuery").length

3

Get all elements containing the word "Cybernetic":

get_elements_by_inner("Cybernetic")

To get the filter method from user1106925 working in <=IE11 if needed

You can replace the spread operator with:

[].slice.call(document.querySelectorAll("a"))

and the includes call with a.textContent.match("your search term")

which works pretty neatly:

[].slice.call(document.querySelectorAll("a"))
   .filter(a => a.textContent.match("your search term"))
   .forEach(a => console.log(a.textContent))

You can do this, not sure if this is recommended but it works for me.

[... document.querySelectorAll('a')].filter(el => el.textContent.includes('sometext'));

You can use a TreeWalker to go over the DOM nodes, and locate all text nodes that contain the text, and return their parents:

const findNodeByContent = (text, root = document.body) => {
  const treeWalker = document.createTreeWalker(root, NodeFilter.SHOW_TEXT);

  const nodeList = [];

  while (treeWalker.nextNode()) {
    const node = treeWalker.currentNode;

    if (node.nodeType === Node.TEXT_NODE && node.textContent.includes(text)) {
      nodeList.push(node.parentNode);
    }
  };

  return nodeList;
}

const result = findNodeByContent('SearchingText');

console.log(result);

<a ...>SearchingText</a>

document.querySelectorAll('a').forEach(function (item) {
    if (item.innerText == 'SearchingText') {
        console.dir(item);
    }
});

This does the job.
Returns an array of nodes containing text.

function get_nodes_containing_text(selector, text) {
    const elements = [...document.querySelectorAll(selector)];

    return elements.filter(
      (element) =>
        element.childNodes[0]
        && element.childNodes[0].nodeValue
        && RegExp(text, "u").test(element.childNodes[0].nodeValue.trim())
    );
  }

Use property called getElementInnerText in script which will fetch inner content of that tag.

document.getElementInnerText('a');