Check out example codes for "random number text in html". It will help you in understanding the concepts better.

Code Example 1

<button class="button" onclick="RandomID();" style="font-family: sans-serif;">RUN</button>
<input class="input" type="text" id="id" name="id" size="3" readonly />

Code Example 2

function RandomID() {
  var value;
  var rnd = Math.floor(Math.random() * 11);

  if (rnd === 7)
    value = "Wassup";
  else if (rnd <= 5)
    value = "Hello";
  else
    value = rnd;

  document.getElementById('id').value = value;
}

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