JSFiddle - React, Tailwind, and code Playground

HTML

<a href="http://www.example.com?iframe">ayres</a>
<a href="http://www.example.com?if=1">nfo</a>
<a href="http://www.example.com?iframe=1">ryes</a>
<a href="http://www.example.com?if=1">no</a>
<a href="http://www.example.com?iframe&sortby=awesomeness">yes</a>

JavaScript

(function($) {

  $.fn.tagName = function() {
    return this.get(0).tagName.toLowerCase();
  }

  $.expr[':'].inHRef = function(obj, index, meta, stack){
  
    if ($(obj).tagName() != 'a')
      return false;
  
    var afi = $(obj).attr('href').split('?'), sfi, txt = meta[3];
    
    if (afi.length == 1)
       return false;
    
    sfi = afi[1];
    
    // Regular Expression
    
    var rgCI = '\\'+sfi+'\\gi';
    
    // case-insensitive
    return (rgCI.match(txt));
    
    var rgCS = '\\'+sfi+'\\g';
    
    // case-sensitive
    //return (rgCS.match(txt));
    
    // IndexOf
    
    // case-insensitive
    //return ( sfi.toLowerCase().indexOf(txt.toLowerCase()) > -1);
        
    // case-sensitive
    //return ( sfi.indexOf(txt) > -1);
    
};

})(jQuery);

$(function() {
    
    $('a:inHRef(iframe)').css('background-color', '#aaaaa0');
    
});