JSFiddle - React, Tailwind, and code Playground

HTML

<button class="set_variable" value="1">Variable = 1</button> 
    <button class="set_variable" value="2">Variable = 2</button> 
    <button class="set_variable" value="3">Variable = 3</button> 

    <div id="tabs" > 
    <ul> 
         <li><a href="ajax.php?func=ajax-func1">Function 1 </a></li> 
         <li><a href="ajax.php?func=ajax-func2">Function 2 </a></li> 
    </ul> 
    </div>

JavaScript

var variable = '';
$( '#tabs' ).tabs({  beforeLoad: function( event, ui ) { 
    if(variable != '')
         ui.ajaxSettings.url += "&variable=" + variable ; 
}}); 

         $('button.set_variable').click(function() { 
             variable = $(this).val(); 
          });