disable submit button after form validation

1<form action="#" method="post" id="myform" name="myform">
2    Location: <input name="location" type="text" />
3    Site: <input name="site" type="text" />
4    Age: <input name="age" type="text" />
5    Gender <input name="gender" type="text" />
6    <input name="button" type="submit" class="myButton" id="button" value="Submit" />
7</form>
8