仅当在输入字段中键入某个单词时，如何启动javascript：alert框？

Question

<script>
var monster = 40
var damage = Math.floor(Math.random()*10)
</script>


<p>Type 'Spark' or 'Fire' to Attack.</p>
<form action="javascript:alert(  'Enemy has' + (monster- damage) + 'Health!' );"
>
  <div>
    <input type="text">
    <input type="submit">
  </div>

</form>
<span></span>


</body>

So this is my code so far I type anything in it gives me a text box saying the Enemy has whatever health, I would like to have it where only if you type spark or fire into the input field you get that text box and if you type something random like skdfslkfha nothing happens (unlike now :/)

Answer 1

JS Fiddle

html

<form action="javascript:ale()">
    <div>
        <input type="text" id="find">
        <input type="submit">
    </div>
</form>

javascript

function ale() {

    a = document.getElementById("find").value
    if (a == 'Spark' || a == 'Fire') {
        var monster = 40
        var damage = Math.floor(Math.random() * 10)
        alert('Enemy has ' + (monster - damage) + ' Health!');
    }
    else{
        alert('worng keyword');
    }

}