鼠标经过选择菜单案例

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
        "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
<head>
    <meta http-equiv="Content-Type" content="text/html;charset=UTF-8">
    <title>Document</title>
    <script>
        window.onload=function(){
            var txt=document.getElementById("txt");
            txt.onmouseover=function()
            {
                this.select();  //鼠标经过自动选择
            }
        }
    </script>
</head>
<body>
<input type="text" id="txt"/>
</body>
</html>