function switchClasses(class1, class2) {
elements = (document.all) ? document.all : document.getElementsByTagName("*");
for (i=0; i<elements.length; i++) {
if (elements[i].getAttribute('class') == class1) {
elements[i].setAttribute('class', class2);
}
else if (elements[i].getAttribute('class') == class2) {
elements[i].setAttribute('class', class1);
}
}
}
setInterval("switchClasses('blink-white', 'blink-black')", 1000);