var cleared = Array();

function clearSpace(field) {
	
	var already = 0;
	
	for (var i=0; i < cleared.length; i++)
	{

		if (cleared[i] == field.name) {
			already = 1;
		}
	}
	
	if (!already) {
		field.value = "";	
		cleared.push(field.name);
	}

}