JSFiddle - React, Tailwind, and code Playground

HTML

<input type="checkbox" onclick="check()" name="checking">j'accepte les conditions
   <input type="submit" value="Valider"  id="valide" disabled/>

JavaScript

function check(){
        if($('input[name=checking]').is(":checked")){
            $("#valide").prop('disabled',false);
        }else{
 $("#valide").prop('disabled',true);
        }
}