JSFiddle - React, Tailwind, and code Playground

HTML

<form action="http://www.google.com" method="get">
<input type="checkbox"/>
<input type="checkbox"/>
<input type="checkbox"/>
<button id="yourButton" type="submit">Click</submit>
</form>

JavaScript

$("#yourButton").click(function(e){
  var n = $("input:checked").length;  //Checkbox count, may need refined
  if(n<2) //using n from above.
  {
    e.preventDefault(); 
  }
});