$('#field').val('');
// Behold the power of JQuery.
$('#myform')[0].reset();
<body>
<form method="" action="">
<input type="text" name="email" class="input" />
<input type="submit" value="Sign Up" class="button" />
</form>
</body>
<script>
$(document).ready(function() {
$(".input").val("Email Address");
$(".input").on("focus", function() {
$(".input").val("");
});
$(".button").on("click", function(event) {
$(".input").val("");
});
});
</script>
$('input:text').filter(function() { return $(this).val() == ""; });