window.onload = function() {
            var inputs = document.getElementsByTagName('input');
            var hoverPattern = /\bhover\b/;
            var addHover = function() {
                if(!this.className.match(hoverPattern))
                    this.className = this.className + " hover";
            }
            var removeHover = function() {
                this.className = this.className.replace(hoverPattern, "");
            }
            for (var i = 0; i < inputs.length; i++) {
                var input = inputs[i];
                if(input.type == 'submit' || input.type == 'button') {
                    input.onmouseover = addHover;
                    input.onmouseout = removeHover;    
                }
            }
        };