鼠标事件分析(onmouseenter、onmouseover、onmouseleave和onmouoseout的区别)
先上个代码123456#biggest,#biggestS{7height:300px;8width:300px;9background-color:cadetblue;10margin:200pxauto;11position:relative;12}13#middle,#middleS{14height:200px;15width:200px;16position:absolute;17bac