var phone_field_length=0;
function TabNext(obj,event,len,next_field)
{
	if (event == "down") {
			phone_field_length=obj.value.length;
			}
		else if (event == "up") {
			if (obj.value.length != phone_field_length) {
				phone_field_length=obj.value.length;
				if (phone_field_length == len) {
					next_field.focus();
					}
				}
			}
	}