var fields = document.getElementsByTagName('input');
for (var i = 0; i<fields.length; i++) {
	fields[i].onfocus = function() {this.className = ' onfocus';}
	fields[i].onblur = function() {this.className = this.className.replace('onfocus', 'onblur');}
}

var fields = document.getElementsByTagName('textarea');
for (var i = 0; i<fields.length; i++) {
	fields[i].onfocus = function() {this.className = ' onfocus';}
	fields[i].onblur = function() {this.className = this.className.replace('onfocus', 'onblur');}
}