// Call example: <input name="username" id="username" type="text" value="Username" onfocus="javascript:autoClearInput('username');" />
function autoClearInput(id_str)
{
	var input = document.getElementById(id_str);
	if (input.value == "e-mail adres") {
		document.getElementById(id_str).value = "";
	} else if (input.value == "Straat") {
		document.getElementById(id_str).value = "";
	} else if (input.value == "Postcode") {
		document.getElementById(id_str).value = "";
	} else if (input.value == "Stad") {
		document.getElementById(id_str).value = "";
	}
}