javascript - Hidden form field but to still show required validation if no set value -

i have form fields populated javascript based on how user interacts webpage.

<input type="hidden" class="evaluation_answer" required name="evaluation_1"/> <div class="options">     <div class="option">         <i class="fa fa-star-o fa-2x"></i>     </div>     <div class="option">         <i class="fa fa-star-o fa-2x"></i>     </div>     <div class="option">         <i class="fa fa-star-o fa-2x"></i>     </div>     <div class="option">         <i class="fa fa-star-o fa-2x"></i>     </div> </div> 

the value field gets populated javascript.

var stars = document.getelementsbyclassname("fa-star-o"); for(var = 0; < stars.length; i++) {     stars[i].addeventlistener("click", function(){         console.log("empty star clicked...");          var sib = this.parentnode.parentnode;         sib = sib.getelementsbytagname("i");         console.log(sib);         for(var u = 0; u < sib.length; u++) {             sib[u].classlist.remove("fa-star");             sib[u].classlist.add("fa-star-o");             sib[u].style.color = "#444";         }          this.classlist.remove("fa-star-o");         this.classlist.add("fa-star");          for(var u = 0; u < sib.length; u++) {             if(sib[u].classlist.contains("fa-star")) {                 var index = u;                 break;             }         }          var hidden_input = this.parentnode.parentnode.parentnode;         hidden_input = hidden_input.getelementsbyclassname("evaluation_answer");         hidden_input[0].value = index + 1; 

this gives hidden input field value depending on index of whatever clicked on page (not important), however, should have not clicked in , still wish submit form, field have no value set. i've tried adding required tag hidden input field, validation popup/alert (chrome) doesn't show.

is there way show these required validation messages?

tl;dr: in chrome, required fields have not been given value alert user that field required upon submission, if set field hidden, doesn't show validation. fix?/workaround? know working intended, i'd prefer validation message.