window.onload?=?function(){
	window.onscroll?=?function(){
		var?top?=?document.documentElement.scrollTop?||?document.body.scrollTop;
		var?menus?=?document.getElementById('menu').getElementsByTagName('a');
		var?items?=?getByClassName("document.getElementById('content')",'item');
		var?currentId?=?"";
		/*console.log(top);*/
		for?(var?i?=?0;?i?<?items.length;?i++)?{
			var?_item?=?items[i];
			var?_itemTop?=?_item.offSet;
			if(top?>?_itemTop?-200){
				currentId?=?_item.id;
			}else{
				break;
			}
		}
		if(currentId){
			for?(var?j?=?0;?j?<?menus.length;?j++)?{
				var?_menu?=?menus[i];
				var?_href?=?_menu.href.split('#');
				if(_href[_href.length-1]?!=??currentId){
					removeClass('_menu','current');
				}else{
					addClass('_menu','current');
				}
			}
		}
	}
}
/*根據(jù)className找元素*/
function?getByClassName(obj,cls){
	var?elements?=?obj.getElementsByTagName('*');
	var?result?=?[];
	for?(var?i?=?0;?i?<?elements.length;?i++)?{
		if(elements[i].className?==?cls){
			result.push(elements[i]);
		}
	}
	return?result;
}
function?hasClass(obj,cls)?{
	return?obj.className.match(new?RegExp("(\\s|^)"+cls+"(\\s|$)"));
}
function?removeClass(obj,cls)?{
	if(hasClass(obj,cls)){
		var?reg?=?new?RegExp("(\\s|^)"+cls+"(\\s|$)");
		obj.className?=?obj.className.replace(reg,"");
	}
}
function?addClass(obj,cls)?{
	if(!hasClass(obj,cls)){
		obj.className?+=?"?"?+?cls;
	}
}

這句話我的拼寫(xiě)沒(méi)錯(cuò)誤??？