鼠标移上时显示，移出时隐藏的效果

参考了百度空间的做法，关键点是不使用display而是visibility来控制是否显示，这样就没有了事件源转移而导致的闪动问题。

<div class="cell">
	<div class='c_opera' style="visibility:hidden;"><a href="#">删除</a></div>										
	<div class="c_title">个人图片</div>
	<div style="position:static;" class='c_logo'><img class='imgStyle' src="http://misc.home.news.cn/blog/images/random_small.jpg" border=0/></div>
	<div class="c_info"><br/> </div>
</div>
		(function() {
			function doOnload() {
				var cell, opera, cellLists = $("mt").getElementsByTagName("div");
				for(var i = cellLists.length - 1; i >= 0; i--) {
					cell = cellLists[i];
					if(cell && cell.className == "cell") {
						opera = getElementsByClassName("c_opera",cell)[0];
						opera.id = "c_opera" + i;
						cell.name = i;
						cell.onmouseover = cellMOver;
						cell.onmouseout = cellMOut;
					}
				}
			}
			function cellMOver(event) {
				$("c_opera" + this.name).style["visibility"] = "visible";
			}
			function cellMOut(event) {
				$("c_opera" + this.name).style["visibility"] = "hidden";
			}
			//附加 onload事件
			EventUtil.addEventHandler(window, "load", doOnload);
		})();