var IS_IE = document.all && window.print && !window.opera && /MSIE [56]/.test(navigator.userAgent);
function addHover(elm) {
  elm.style.behavior = " ";
  elm.onmouseenter = function() {
  this.className+= ' hover';
  }
  elm.onmouseleave = function() {
    this.className = this.className.replace(/\bhover\b/,"");
  }
}