JSFiddle - React, Tailwind, and code Playground

HTML

<span class="positio" >span1</span>
<span class="someClass position111" >span2</span>
<span class="someClass" >span3</span>
<span class="someClass position2" >span4</span>
<span class="someClass" >span5</span>
<span class="someClass position4" >span6</span>
<span class="someClass position10" >span7</span>
<span class="someClass" >span8</span>
<span class="someClass position12" >span9</span>

JavaScript

jQuery.expr[':'].regex = function(elem, index, match) {
    var matchParams = match[3].split(','),
    validLabels = /^(data|css):/,
    attr = {
        method: matchParams[0].match(validLabels) ? 
                    matchParams[0].split(':')[0] : 'attr',
        property: matchParams.shift().replace(validLabels,'')
    },
    regexFlags = 'ig',
    regex = new RegExp(matchParams.join('').replace(/^\s+|\s+$/g,''), regexFlags);
    return regex.test(jQuery(elem)[attr.method](attr.property));
}
$("span:regex(class, position[0-9])").css("background-color", "Green");