Вот мое решение.Я обнаружил, что есть два способа добиться этого.В Firefox вы можете использовать selection api .К сожалению, это не будет работать в Chrome.Более простое решение - просто сопоставить текст поиска и выделить его, заключив его в теги <mark>.
var opar = document.getElementById('paragraph').innerHTML;
function highlight() {
var paragraph = document.getElementById('paragraph');
var search = document.getElementById('typed-text').value;
search = search.replace(/[.*+?^${}()|[\]\\]/g, '\\$&'); //https://stackoverflow.com/questions/3446170/escape-string-for-use-in-javascript-regex
var re = new RegExp(search, 'g');
var m;
if (search.length > 0)
paragraph.innerHTML = opar.replace(re, `<mark>$&</mark>`);
else paragraph.innerHTML = opar;
}
<div id="highlights">
<div class="container">
<div class="row">
<div class="col-md-12" id="paragraph">
<p>
Robotics is an interdisciplinary branch of engineering and science that includes mechanical engineering, electronics engineering, information engineering, computer science, and others. Robotics deals with the design, construction, operation, and use of
robots, as well as computer systems for their control, sensory feedback, and information processing. These technologies are used to develop machines that can substitute for humans and replicate human actions. Robots can be used in many situations
and for lots of purposes, but today many are used in dangerous environments (including bomb detection and deactivation), manufacturing processes, or where humans cannot survive (e.g. in space). Robots can take on any form but some are made to
resemble humans in appearance. This is said to help in the acceptance of a robot in certain replicative behaviors usually performed by people. Such robots attempt to replicate walking, lifting, speech, cognition, and basically anything a human
can do. Many of today's robots are inspired by nature, contributing to the field of bio-inspired robotics. The concept of creating machines that can operate autonomously dates back to classical times, but research into the functionality and
potential uses of robots did not grow substantially until the 20th century.[1] Throughout history, it has been frequently assumed that robots will one day be able to mimic human behavior and manage tasks in a human-like fashion. Today, robotics
is a rapidly growing field, as technological advances continue; researching, designing, and building new robots serve various practical purposes, whether domestically, commercially, or militarily. Many robots are built to do jobs that are hazardous
to people such as defusing bombs, finding survivors in unstable ruins, and exploring mines and shipwrecks. Robotics is also used in STEM (science, technology, engineering, and mathematics) as a teaching aid. Robotics is a branch of engineering
that involves the conception, design, manufacture, and operation of robots. This field overlaps with electronics, computer science, artificial intelligence, mechatronics, nanotechnology and bioengineering.
</p>
</div>
<div class="col-md-12 input-group mt-3">
<div class="input-group-prepend">
<span class="input-group-text" id="basic-addon1">
<i class="fas fa-pencil-alt"></i>
</span>
</div>
<input id="typed-text" type="text" class="form-control" placeholder="Type text" onkeyup="highlight()">
</div>
</div>
</div>
</div>
Идея очень проста.При событии keyup (когда пользователь заканчивает нажимать клавишу), функция highlight будет искать все вхождения в тексте и затем подсвечивать их, используя теги <mark>.