JSFiddle - React, Tailwind, and code Playground

HTML

Wie heißt der Kaiser von 
<input type="text" id="input_answer" value="" />
<input type="button" value="Prüfen" onClick="checkInput('input_answer','answer_div','china')"/>
<DIV id="answer_div"></DIV>

CSS

.wrong {
    display: block;
    color: red;
}
.correct {
    display: block;
    color: green;
}
#answer{
  display:inline;
  font-family:Arial,Sans-Serife;
}

JavaScript

function checkInput(elInput,elAnswer,strAnswer){
    var eltarget = document.getElementById(elAnswer);
    var elInput = document.getElementById(elInput);
   if(elInput.value.toLowerCase() == strAnswer.toLowerCase()){
        eltarget.innerText = "KORREKT";
        eltarget.setAttribute("class","correct");
   }else{
        eltarget.innerText = "FALSCH";
        eltarget.setAttribute("class","wrong");
   }
}