stuHover = function() {
				var cssRule;
				var newSelector;
				for (var i = 0; i < document.styleSheets.length; i++)
					for (var x = 0; x < document.styleSheets[i].rules.length ; x++)
					{
						cssRule = document.styleSheets[i].rules[x];
						if (cssRule.selectorText.indexOf("LI:hover") != -1)
						{
							newSelector = cssRule.selectorText.replace(/LI:hover/gi, "LI.iehover");
							document.styleSheets[i].addRule(newSelector , cssRule.style.cssText);
						}
					}
					var getElm = document.getElementById("nav").getElementsByTagName("LI");
					for (var i=0; i<getElm.length; i++) {
						getElm[i].onmouseover=function() {
					this.className+=" iehover";
				}
				getElm[i].onmouseout=function() {
					this.className=this.className.replace(new RegExp(" iehover\\b"), "");
				}
			}
		}
		if (window.attachEvent) window.attachEvent("onload", stuHover);

		function changeImage(num,typs){
				var imgs = document.getElementById('but'+num);
				imgs.src = 'images/button/but'+num+typs+'.jpg';
		}