JavaScript onsubmit Event

<!doctype html>
<html>
<head>
<title> onsubmit</title>
</head>
<body>
<script>
function formsubmit(){

alert("your form submit..!")

}
</script>

<form onsubmit="formsubmit()">
<label> User name </label>
<br>
<input type="text" id="txt">
<br>
<button type="submit"> Submit </button>

</form>

</body>
</html>