function suckerfish(type, tag, parentId) {
if (window.attachEvent) {
window.attachEvent("onload", function() {
var sfEls = (parentId==null)?document.getElementsByTagName(tag):document.getElementById(parentId).getElementsByTagName(tag);
type(sfEls);
});
}
}
sfFocus = function(sfEls) {
for (var i=0; i<sfEls.length; i++) {
sfEls[i].onfocus=function() {
this.className+=" sffocus";
}
sfEls[i].onblur=function() {
this.className=this.className.replace(new RegExp(" sffocus\\b"), "");
}
}
}

suckerfish(sfFocus, "INPUT");
suckerfish(sfFocus, "TEXTAREA");