<!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title>form空白</title> <script type="text/javascript"> window.onload = function(){ var btnEle = document.getElementById("btnSub"); btnEle.onclick = function(){ //1.取用户名值 var uname = document.getElementById("username").value; if(uname == null || "" == uname){ alert("用户名不能为空，请重新输入！"); // var yOn = confirm("确认删除吗？"); // alert(yOn); //取消默认行为 return false; } } } </script> </head> <body> <h1>登录</h1> <form action="login_success.html"> <table> <tr> <td>用户名:</td> <td><input type="text" name="username" id="username"></td> </tr> <tr> <td align="right">密码:</td> <td><input type="password" name="pwd"></td> </tr> <tr> <td colspan="2" align="center"> <input type="reset"> <input id="btnSub" type="submit" value="登录"> </td> </tr> </table> </form> <a href="../index.html">回首页</a> </body> </html>