模拟windows平台的上下文菜单

时间：2011-03-10 来源：chemdemo

技术上没什么难的，就是定义一个隐藏的box，当触发上下文事件时显示它，当单击body任意处时又隐藏它。样式效果比较粗糙，请见谅~~~

Demo在这里

结构：

View Code

 1 <div id="wrap">
 2     <ul id="menu">
 3         <li><a href="">撤销</a></li>
 4         <li><a href="">重做</a></li>
 5         <li><a href="">复制</a></li>
 6         <li><a href="">粘贴</a></li>
 7         <li><a href="">大小写转换</a></li>
 8         <li><a href="">回车</a></li>
 9         <li><a href="">拼写检查</a></li>
10         <li><a href="">新建</a></li>
11         <li><a href="">自定义</a></li>
12         <li><a href="">图形选项</a></li>
13         <li class="no"><a href="">关闭</a></li>
14     </ul>
15  </div>

code是这样：

function $(id) {
        return document.getElementById(id);
};

var EventUnit = {
        addHandler: function(element, type, handler) {//添加事件处理程序
                if(element.addEventListener) {
                        element.addEventListener(type, handler, false);
                } else if(element.attachEvent) {
                        element.attachEvent('on' + type, handler);
                } else {
                        element['on' + type] = handler;
                };
        },
        getEvent: function(event) {
                return event ? event : window.event;
        },
        preventDefault: function(event) {//取消事件默认动作
                if(event.preventDefault) {
                        event.preventDefault();
                } else {
                        event.returnValue = false;
                };
        }
}

EventUnit.addHandler(window, 'load', function() {
        var wrap = $('wrap');
        var menu = $('menu');
        var menuStyle = menu.style.display;
        var x = wrap.offsetLeft + wrap.clientWidth, y = wrap.offsetTop + wrap.clientHeight;
        var w = 0, h = 0;
        var left = 0, top = 0;

        EventUnit.addHandler(wrap, 'contextmenu', function(event) {
                event = EventUnit.getEvent(event);
                EventUnit.preventDefault(event);

                menu.style.display = 'block';
                w = menu.clientWidth;
                h = menu.clientHeight;
                left = (x - event.clientX >= w) ? event.clientX - wrap.offsetLeft : event.clientX - wrap.offsetLeft - w;
                top = (event.clientY + h <= y) ? event.clientY - wrap.offsetTop : event.clientY - wrap.offsetTop - h;
                menu.style.left = left + 'px';
                menu.style.top =  top + 'px';
        });

        EventUnit.addHandler(document, 'click', function() {
                menu.style.display = menuStyle;
        });
});