function next1() {
	if (document.form_ambikey.s1.value.length == 4) {
		document.form_ambikey.s2.focus();
	}
}

function next2() {
	if (document.form_ambikey.s2.value.length == 4) {
		document.form_ambikey.s3.focus();
	}
}

function next3() {
	if (document.form_ambikey.s3.value.length == 4) {
		document.form_ambikey.s4.focus();
	}
}