function buttons() {
      var inputs = document.getElementsByTagName("input");
      var i=0;
      for (i=0; i<inputs.length; i++) {
        if(inputs[i].getAttribute('type') == 'image') {
          var image = inputs[i];
          image.offImage = new Image();
          image.offImage.src = image.src;
          image.onImage = new Image();
          image.onImage.imageElement = image;
          if (navigator.userAgent.toLowerCase().indexOf('safari') != - 1) {
            image.onmouseover = function() { this.src = this.onImage.src; };
            image.onfocus = function() { this.src = this.onImage.src; };
            image.onmouseout = function() { this.src = this.offImage.src; };
            image.onblur = function() { this.src = this.offImage.src; };
          } else {
            image.onImage.onload = function() {
            this.imageElement.onmouseover = function() { this.src = this.onImage.src; };
            this.imageElement.onfocus = function() { this.src = this.onImage.src; };
            this.imageElement.onmouseout = function() { this.src = this.offImage.src; };
            this.imageElement.onblur = function() { this.src = this.offImage.src; };
          };
        }
        image.onImage.src = image.src.replace(/-off./, '-on.');
        }
      }
    }
    window.onload=buttons;