<!DOCTYPE html>
<html>
<body>
<form target="_blank">
First name: <input type="text" name="fname" value="Donald"><br>
Last name: <input type="text" name="lname" value="Duck"><br>
<input type="submit" id="mySubmit" formaction="/action_page.php" formmethod="get" value="Submit">
</form>
<p>Click the "Change formmethod" button to change the formmethod of the submit button in the form above.</p>
<button onclick="myFunction()">Change formmethod</button>
<p id="demo"></p>
<script>
function myFunction() {
document.getElementById("mySubmit").formMethod = "post";
document.getElementById("demo").innerHTML = "The formaction is now 'POST'.";
}
</script>
</body>
</html>