function plius (id) {
	var field = document.getElementById(id);
	var increment = field.value;
	increment++;
	if (isNaN(increment)) field.value = 1;
	else field.value = increment;
}
function minus (id) {
	var field = document.getElementById(id);
	var decrement = field.value;
	decrement--;
	if (isNaN(decrement) || decrement < 0) field.value = 0;
	else field.value = decrement;
}

	function changeGavejoLentele(id) {
		var viso = 2; // pakeiciame kiek yra is viso
		var divArray = new Array(viso);
		// Suvedame visus naudojamus 
		// skaiciuoti pradedame nuo 0.
		divArray[0] = "gavejasMoketojas";
		divArray[1] = "gavejasNemoketojas";

		if (document.all || document.getElementById) {
			for (i = 0; i < viso; i++) {
				if (id == i) document.getElementById(divArray[i]).style.display = '';
				else document.getElementById(divArray[i]).style.display = 'none';
				}
			return;
			} 
	}
	
	function changePristatymoLentele(id) {
		var viso = 2; // pakeiciame kiek yra is viso
		var divArray = new Array(viso);
		// Suvedame visus naudojamus 
		// skaiciuoti pradedame nuo 0.
		divArray[0] = "iNamus";
		divArray[1] = "iDarba";

		if (document.all || document.getElementById) {
			for (i = 0; i < viso; i++) {
				if (id == i) document.getElementById(divArray[i]).style.display = '';
				else document.getElementById(divArray[i]).style.display = 'none';
				}
			return;
			} 
	}