a/20049344/1636522

HTML

<input id="search" value="^()\w\d$" />
<button id="submit">Highlight!</button>
<button id="revert">Revert!</button>
<p id="sample">sample string li $pan style="color:red" id <span id="toto" style="">color id style</span> abcde</p>

CSS

b {
    color:red
}

JavaScript

$('#submit').click(function () {    
    $('#sample ').html(function(i, html){
        var regexp = new RegExp($('#search').val().split('').join('(?:<.*?>)?') + '(?=[^>]*(<|$))', 'g');
        return html.replace(regexp, '<b class="highlight">$&</b>');
    });
});

$('#revert').click(function(){
    $(".highlight").contents().unwrap();
});