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<!DOCTYPE html>
<html>
<body>
<p>Click the button to create a LEGEND element with some text.</p>
<fieldset id="myFieldset">
  Name: <input type="text">
</fieldset><br>
<button onclick="myFunction()">Try it</button>
<script>
  function myFunction() {
    var x = document.createElement("LEGEND");
    var t = document.createTextNode("Personalia:");
    x.appendChild(t);
    document.getElementById("myFieldset").appendChild(x);
  }
</script>
</body>
<!-- /jsref/tryit.asp?filename=tryjsref_legend_create 
</html>