function over(element, number) {
	if (document.getElementById) {
		var img = element.getElementsByTagName('img');
		
		img[0].src = 'images/item' + number + '-thumb-hover.jpg';
	}
}

function out(element, number) {
    if (document.getElementById) {
        var img = element.getElementsByTagName('img');
        
        img[0].src = 'images/item' + number + '-thumb.jpg';
    }
}

function clearField(element, text) {
	if (document.getElementById) {
		if (element.value == text) {
			element.value = ''; 
		}
	}
}

function checkValue(element, from, to, text) {
	if (document.getElementById) {
		var value = Number(element.value);
		
		if (isNaN(value)) {
			element.value = text;
		} else {
			if (value < from || value > to) {
				element.value = text;
			}
		}
	}
}