if(document.getElementById) {
	if (document.getElementById('ID_session_edk')) {
		document.getElementById('ID_session_edk').value = '';
	}
}
else if(document.all) {
	if (document.all['ID_session_edk']) {
		document.all['ID_session_edk'].value = '';
	}
}
else if(document.layers) {
	if (document.layers['ID_session_edk']) {
		document.layers['ID_session_edk'].value = '';
	}
}