JSFiddle - React, Tailwind, and code Playground

HTML

<input id="bookroom_1" class="button_small" type="Button" value="Buchen" />
<input type="hidden" name="ident_115" id="ident_115" value="115" />

JavaScript

$("#bookroom_1").click(function(){
 alert($(this).attr("value"));
 alert($(this).next().attr("value"));
});